2339: What a night. Three fascinating sets. And all set up for a fabulous final on Sunday. BBC Two coverage starts at 1400 GMT, BBC Radio Five live web commentary kicks off at 1400, while BBC Radio Five live gets in on the action from 1600 after the football. So that's it - the Argentine in a vest up against the grinding Russian. Caroline Cheese is in the hotseat while Piers Newbery continues his late night efforts in the O2 Arena. It's been a pleasure - night folks.

BBC Sport's Piers Newbery Tweeting from the O2 Arena: "Juan Martin del Potro's press conference will be at midnight," say the lovely people at the ATP desk. It's lucky they're lovely..."

Del Potro after the win courtside: "I feel tired. I am happy to make my final. Thank you for the support - you helped me to keep fighting." And then he ends with a phenomenal revelation - "I am still single!"

Del Potro 6-7 (1-7) 6-3 7-6 (7-3) Soderling
And it's a brilliant rally that opens the tie-breaker. Every shot a blistering boom from the back and Delps eventually fires on into the corner. Last set he'd be pumping his fist. This time, he's barely got the energy to lift his head. Delps grabs the first four points. Wasn't expecting this. But Soders gets an ace - his 16th of the match - to get on the board. 4-1. Delps steadies his nerve by bouncing on his feet. He clips the net and unluckily the ball goes flying high and long. Soderling battles brilliantly to get everything back but his forehand finally flops into the net. He looks gutted. Four match points. I don't really want either player to lose this. Been an explosive match. And that's it. Delps looks to the sky/roof and there's the handshakes. Delps screams to the crowd. DELPO WINS.

Del Potro 6-7 (1-7) 6-3 6-6 *Soderling
Soders steps it up and forces an error from Delps at 15-15. It's soon 40-15 as Soders struggles at the back of the court and plants one long. Careless. Nerves come crashing down on Delps this time and he goes into the net. It's TIE-BREAK TIME after Soders wearily goes wide.

Del Potro* 6-7 (1-7) 6-3 5-6 Soderling
Third double fault for Soders and it's 15-15. Delps has a chance and his forehand crashes into the tape. His head falls into his hands. Tension shows on the server's face and it's another double fault and it's 30-30. Delps goes long though with an easy shot and he's gutted. He swipes the air like a man grabbing an irritating fly. Big serve, big game and it's game for the Swede. Well done sir.

Del Potro 6-7 (1-7) 6-3 5-5 *Soderling
I'm not going to mention a goatee beard threat again in case I'm accused of being too much of a comedian but serves are holding strong and so they need to be for Delps. But he calmly dispatches several missiles to level the match again. This is turning out to be a grinding, cracking and compelling match.

David Lloyd Edinburgh ladies tennis team, via text 81111: "Come on DelPo - Davydenko & Soderling would be a great final but as we were at their match last night & have tickets for the final, we're hoping f or a Delpo victory!! We came all the way from Edinburgh who would have thought we would see same match twice!"

Del Potro* 6-7 (1-7) 6-3 4-5 Soderling
Howls of agony as Delps knocks one long. He had a chance there. Soders has been a bit quiet over the last few games - played quite conservatively. He's staying strong though, mainly thanks to a serve that would seriously damage your health if it hit you. Easy service game and he's one away from a victory and a spot in the final. Anything left in the locker for Delps?

Del Potro 6-7 (1-7) 6-3 4-4 *Soderling
Davydenko still wondering who he'll be playing on Sunday. Two great returns and Delps looks a broken man again. Massive sighs from his coach. Big serve gets him back to 15-30. This is the crunch game. Delps needs to wind the serve up. Or slice one into the corner off the top of the net and force Soders to play into the net. Yep - it's 30-30. And then an ace. Game over and all square. Brilliant composure at a crucial time for a 21-year-old.

BBC Sport's Piers Newbery Tweeting from the O2 Arena: "A suited and booted Greg Rusedski wanders into the media centre and looks up at the big screen. You could have taken these two, Greg.."

Del Potro* 6-7 (1-7) 6-3 3-4 Soderling
He's not the US Open champion for nothing. Delps fires another glorious winner past Soders and takes the first point. Great comeback. Soders has eased into another gear and Delps is being really stretched and moved to all corners of the court. Crunch time and Soders looks stronger and more up for the battle. A brilliant forehand from Delps lands at Soders feet and it's into the net. Crowd noise is electric. More grizzly bear roars and Delps is right back. This man doesn't know when he's beaten. He breaks and the game's in the balance again...brilliant spectacle.

Del Potro 6-7 (1-7) 6-3 2-4 *Soderling
Soders defends the serve well but he sends a couple long and looks to his coach and shrugs his shoulders. Delps will be delighted to see that. A booming forehand gets him within one point of the game but Soders strikes a cracker bang into the far corner of the court. It's deuce and it's nervy times. A phenomenal backhand and Delps has no answer. His first break point of the match. Amazing. And Delps looking a little flat-footed and it's there....Soders has a crucial lead. Delps was firing five minutes ago - where's all that gone?

Anon, via text 81111: "I don't think anyone could honestly say they predicted a Sod V Davy final. But, based on the play during this tour final, it could make for being the most interesting of all matches and one I certainly hope for."

Oscar and Yvonne courtside at the O2, via text 81111: "the atmosphere is has reached boiling point as Del Pots cruises to a set victory! Will it be a homerun for the brooding Argentine!"

Del Potro* 6-7 (1-7) 6-3 2-3 Soderling
An easy service game for Soders. Delpo probably just having a breather but Soders fighting for everything.

Del Potro 6-7 (1-7) 6-3 2-2 *Soderling
I know you don't need reminding but remember there's live commentary on BBC Radio Five live extra. The Swedish flags get waved around frantically as they cheer on their boy. Leading 15-0, Soders again charges to the net and has a relatively easy volley to go 30-0 but pushes it just wide. He challenges the call but I think he knew. Desperate stuff. Delps then pulls a Christmas cracker out. In trouble mid-rally but a backhand special goes blazing past Soders. Stunning. He's back in control of his service game. Arms aloft after Delps recovers a beauty. He's pushed into the corner and some how pushes it back down the line for the winner. Soders can't believe it. The crowd love it. The Swede does not.

Del Potro* 6-7 (1-7) 6-3 1-2 Soderling
Soders ups his game and the aggression's back. He charges to the net and smashes a winner. According to the stats, Delps has yet to hit a volley. A missile serve shoots wide of Delps' backhand and he can't get it back. Game over.

Del Potro 6-7 (1-7) 6-3 1-1 *Soderling
An unbelievable recovery from Delps - in trouble at the back and he pulls a backhand out of the top drawer to drop at the feet of Soders to make it 40-0. An easy service game.

ajt_1989 on 606: "Del Potro is gunna be the next guy to dominate the mens game. I'm a Murray fan, and i think the difference in class is pretty evident. Winning this tournament will send a warning out to the top four for next year.."

Del Potro* 6-7 (1-7) 6-3 0-1 Soderling
Soders looks a little rattled. He's the one to wave his clenched fist around - bit of mind games perhaps? A big smash and it's soon game over.

TeleKemis on 606: "what a weeks tennis this has been. One of the best weeks of tennis standard-wise I have seen for a long-time."

Tom on 606: "Sod crumbles slightly and Del P wins the BP. Will the difference in class and mentality now start to show?"

Del Potro 6-7 (1-7) 6-3 *Soderling
Two opening points are shared with a dabble of magic from both. More Soders magic with a cracking winner and Delps is in danger of letting the initiative slip. Big serve helps him out, for now. A looping ace - confirmed after a challenge - and DelP roars like a grizzly bear. A wild Soders forehand gives him the set. DelP in three? It's on.....

Del Potro* 6-7 (1-7) 5-3 Soderling
Soders winds up the pressure with more explosions coming from his serving racket. Goes to 30-0 but Delps stuns the Swede with a brilliant backhand winner. Soders can only watch and admire. A fabulous and relentless rally from the baseline and Delp takes it to 40-30 after a drop shot. What? Yep, you read right. He mixes it up and drops one in short to catch Soders off guard. He waves his arms to encourage the crowd and BOOM - the ball comes flying back to give break point. Turning point? Soders is struggling a little with his serve. He plays it long and FINALLY there's a break. DelP is back on it. He's shouting, he's fired up and back in this match. Serving for the set.

ProfCapelo on 606: "One thing that is really impressive, and different, in Solderling's game is the confidence and self-belief with whih he gets himself out of trouble when playing the top guys. Here again, and not the first in this match, he saves a break down and comes right back. Go Sod!"

Del Potro 6-7 (1-7) 4-3 *Soderling
DelP looking the slightly stronger player. Goes 40-0 up and then gets sloppy. Quite an easy service game though on the whole. A strange match this. Can't quite put my finger on it. Intriguing, make no mistake. A place in the final up for grabs against Davydenko.

Del Potro* 6-7 (1-7) 3-3 Soderling
Is this a chance for a break? DelP grabs the opener but Soders charges back, takes control mid-court and plants the winner wide of the scampering Delps to make it 15-15. And BOOM. DelP opens up his shoulders and cracks one through to edge closer to a rare break - but guess what? You guessed it - the serves come flying back like an act of revenge and it's deuce, and then adv Soders, and then game.

Anon at the O2, via text 81111: "Watching from high up in O2. Very flat game after great earlier semi. Want a delp victory but think soders is going to get it"

Del Potro 6-7 (1-7) 3-2 *Soderling
Who's the man who cranked up his serve by 15% there? DelP indeed. Takes the game without dropping a point. Still no break in this match.

Del Potro* 6-7 (1-7) 2-2 Soderling
DelP gets down on one knee and has a chance to pass Soders but it flies agonisingly into the net. He tries another winner with a backhand to the rear of the court but it's not to be. Easy pickings for the Swede.

Del Potro 6-7 (1-7) 2-1 *Soderling
Del Potro looking in control but he sends one long to give Soders a sniff. A steady serve though sees him through. He's continuing to appear a little out of sorts.

Del Potro* 6-7 (1-7) 1-1 Soderling
A solid service game and it's all level. I have no idea how DelP is going to break this tower of a man.

Del Potro 6-7 (1-7) 1-0 *Soderling
DelP settles his game and cruises to a service game. Soderling totally deserves this overall lead though. He's making all the moves and really forcing Delp into a lot of mistakes. And generally speaking, bar a couple of Delp firecrackers, the only reason he's losing points at the moment is him playing aggressive shots wide of the line. DelP really needs to raise his game. Quickly as well.

ProfCapelo on 606: "Robin Solderling is certainly the most improved player of the year, considering the injuries and the ups and downs he has gone through over the years."

Del Potro 6-7 (1-7) Soderling
A first double fault from DelP gives Soders a 2-0 lead and the Argentine's head is bowed as he plays a sloppy one and trails 3-0. It's soon 4-0 after a lacklustre forehand flops into the net. DelP tries a winner down the left side and it's dragged wide. Not good. Bottled it? Just mistakes really. They change ends and Soders has a 5-1 lead healthier than my three bean salad. A shocking forehand gives Soders five set points. He looks tired. And an ace ties it up. 139 mph - his quickest of the night.

Del Potro 6-6 *Soderling
A strange kick-up from the ball gives Delp the first point. Soders looks confused but he hits back with a stunning forehand drive using both hands to make it 15-15. Nice rally, nice winner. And then DelP throws one right back in his face. Anything you can do, I can do better. His fifth ace and he's one point away from sending it to a tie-break. If I died tonight and came back as a tennis ball, I would be extremely unhappy if I ended up in the O2 tomorrow lunch time. These boys hit these balls like they hate the yellow little fellas. It's tie-break time after 43 minutes.

WOW on 606: "its quite apparent that sod is handling delpo's serve better than fed did. he is not returning it by slicing rather a forceful return. sod to come good if delpo drops his first serve percentage."

Del Potro* 5-6 Soderling
The slightly more aggressive Soders plants one just long and wide to leave me and my shaver quaking slightly. The Swede is the one player mixing it up a little more and gets back to 15-15 but then nervously pushes it wide. I want a rally. Is that so wrong? Serve dominated right now. Nice rally at 40-30 gives Soders the game which ends with a clever and calm smash. My chin is safe for now. Phew. Can you deliver again DelP?

Del Potro 5-5 *Soderling
31 minutes gone and no service break. The 10th game begins and Soders grabs a brilliant winner down Delp's backhand to take it to 15-15. Two more swipes and it's 40-15 but then up pops the Swede with a fine low winner picked up brilliantly when on his knees. Tense times at the "business end". Still no break. Odds on a tie-break? I'll wear a goatee beard for a week if this doesn't go 6-6.....big fighting talk that is...

Del Potro* 4-5 Soderling
Soders is sporting a goatee. FACT. Half a one anyway. I'm not happy with that. But who am I to judge? I did try it once but only last 36 hours. A huge serve game (another one) from Soders and gets within one of the set. Can DelP handle the pressure with his service?

LeeD22 on 606: "Del Potro's forehand is arguably the best shot in tennis at the moment! He deserves to make the final for that alone."

Del Potro 4-4 *Soderling
So who will make Sunday's final against Davydenko? All pretty tight so far. Could Soders hope for a quick one having been up late might playing? Fit boy those this one. At this stage of the tournament, fitness has got to be a massive factor. Another love game from Delp.

Del Potro* 3-4 Soderling
A successful challenged line-call from Soders avoids a third double fault and he takes a 40-15 lead before the tape gives DelPots hope of getting back in it. The serving arm winds up and down the ball comes to give DelP no chance.

Del Potro 3-3 *Soderling
DelPots wins the game in a matter of seconds. Wins with a sweet ace as well that flies through and whacks the linesman on top of his head. He closed his eyes and looped his header to the left. Never close your eyes when you head the ball, that's what I've always been told.

Del Potro* 2-3 Soderling
More rather large serves from the Swede. He needed them to get it back to 30-30. DelPots strolls into the middle of the court mid-rally and whacks that ball for a winner like a man on a serious mission. Eyes are very focused tonight. Soders's serve heads up to 137mph. These tennis balls must be burning. Great game. The Swede wins the game by challenging a line call.. interesting.
* denotes next to serve

Del Potro 2-2 *Soderling
Best winner of the day so far. Bounces up nicely for DelPots but there was no guessing what was coming next. He pulls back the trigger and the forehand flies back into the right corner and there's nothing Soders can even do about it. A blur of tennis ball that was. I hope that linseperson is getting paid danger money. Or wearing a crash helmet.
* denotes next to serve

2109: David Haye is introduced to the crowd. Massive applause. And why not? World champion and he's wearing a polar bear leg around his neck. I jest - it's a necklace but it's massive. Haye's broken the 'no more than two buttons undone' rule. Top bloke though.

Del Potro* 1-2 Soderling
Soders surprisingly looks a little shaky and goes down 0-40 on his serve. Umpire over-rules a tight call out wide and Soders stays in it. A big serve gets him back to deuce. Class and all under big pressure. DelPots playing very defensively against the serve. And Soders grabs it. Great comeback after trailing 0-40. That'll hurt a little bit for DelPots.
* denotes next to serve

Oscar and Yvonne at the O2, via text 81111: "We are enjoying the match courtside - predicting a Del Potro victory in a tight 3 set match!"

Del Potro 1-1 *Soderling
DelPots at 21 is the youngest man in the competition and it's all a bit scratchy with DelPots slipping at the back. He hasn't settled yet but his windmill arm and rather poor beard help him to level things up.
* denotes next to serve

Del Potro* 0-1 Soderling
Soders starts brightly. Solid serves and forcing things at the net. Lively. A little wild from Del Pots as he struggles to find his range. Opener to the Swede in a couple of very quick minutes.
* denotes next to serve

BBC Sport's Piers Newbery Tweeting from the O2 Arena: "Changed my mind, super rob in 3. David haye hamming it up below me, reckon delpo could run him close"
Never had this boy down as a wavering indecisive type. Pathetic.

2054: Soderling's sporting a super-bright blue shirt. Looks more like a cheap Sunday morning football kit. That's Soders for you. No fireworks, no frills, but does a job - probably a very comfortable top. DelPots. Headband and boosh - there's my favourite garment - a big steaming black vest with a white spotted stripe thing going across his semi-barrelled chest. DelPots wins the fashion stakes. He's also unshaven. Mrs DP probably not happy with that. One minute to go in the arm-up.....so the great debate....fan of the vest?

dave in peterborough, via text 81111: "I've got 100 quid on JMDP to win the whole thing at 12/1 so can you guess who i'm rooting for?"

2048: Soderling strolls up casually in the darkness of the O2. He's looking relaxed. Bit more noise in the crowd as Del Potro walks out. Massive wave from the Argentine in his black shorts that would probably work as a trouser for your average sized person. Does he have a vest lurking under that huge white tracksuit top?

Robin Soderling before walking out into the arena: "I'm feeling good. I got a two hours rest last night. I believe in myself and hopefully I will have a chance." And Del Potro? The US Open champ says: "I have a very tough match today but I will try my best. I will change my style a little. We will see what happens." Here comes the heartbeat they play over the speakers....here we go.....

BBC Sport's Piers Newbery Tweeting from the O2 Arena: "I can hear the sounds of a robin soderling intro and I never like to miss that so heading into the arena. Too close to call... Delpo in 3?"

2042: Hands up. Can you see me? Yep, I'm holding both arms up and waving them in the air like I don't care. A big boo-boo to start the evening with. See three comments below. I've shockingly Iriana Davydenko suggested Nikolay's wife is a he. She clearly is a she. Official. Sorry Mrs D. That three bean salad has clearly played havoc with my brain. I hope she forgives me.

clareisle on 606: "Hope Sod wins to night as I don t want Potty to overtake Andy in the rankings then Davy to win the event as I dont really like the Sod and I think Davy should win a big one."

Boxing world champion David Haye at the O2 to see Roger Federer!: "I don't follow tennis that much but I'm looking forward to it." He also reveals he's not very good at tennis!

Iriana Davydenko (who is also a psychologist) on her husband's win over Federer: "I am very happy. He works very hard. He played better today. I believe in him all the time. I believe he can win."

2028: Silverware is not the only thing on the line this weekend. Andy Murray will be watching intently with his number four ranking under increasing threat. If Del Potro (ranked five) wins the tournament tomorrow he will switch places with Muzza. So what are your predictions? Del Pots in three I said earlier. Two cups of tea and a sensational three bean salad, complemented with a full bowl of potato salad, has not encouraged me to change my mind.

2024: BBC Radio Five live sports extra has all the commentary for you, and why not at the same time follow all the action in a live text format right here, right now. Look out for Tweet updates from BBC Sport's Piers Newbery who's battling some wobbly technology at the O2. With just over 20 minutes to go, let's get interactive. That means YOU get creative and you do some work. Text 81111,606 or Twitter

2018: Five down, three to go. Hopefully the O2 Arena will have mopped up the tears of the world number one this afternoon after Federer lost out to Nikolay Davydenko in three topsy-turvy sets. So who will meet tennis's equivalent of Cliff Thorburn? (Grinder) We've got a lanky explosive Argentine who's rather partial to a vest (and who the heck isn't?) and on bloomin' fire right now, up against the mighty tireless Sodders aiming to be the first Swede since 1990 (Stefan Edberg) to reach the last two of the ATP Tour World Finals. Thoughts? Predictions? Kick off at around 2045 GMT. Fancy being part of the build-up?