1626: I'm just closing shop so thanks for all your comments. Read the Nadal v Berdych report here thanks to the prose of Mr Newbery. And why wouldn't you return just before 2000 GMT for a drizzle of Roddick v Djokovic? Nothing going on tonight is there? Let's hope Novak has sorted his contact lens. Roddick needs to win in straight sets. Fireworks guaranteed. In the mean time, why not check out the tweets from Piers Newbery who is probably strolling around the O2 trying to bag a quick kick-around with Diego Maradona. I'll be back a bit later. I'll also be on twitter if you wish to continue the banter. See you later.

Piers Newbery on Twitter: "I would prefer to play against someone a little bit easier," says Rafa when asked if he is happy to face Murray. He's being sarcastic too."

Matt in Southampton, via text 81111: "Spaghetti bolognaise. I was making one then saw the tennis was on so have one of the girls in my corridor make it so i could sit back in my cold room and watch it in my bed"
Not a bad life eh?

Ian in Winchester, via text 81111: "Nadal is the most stubborn, determined, gritty snarling sportsman currently playing any sport. He just refuses to lose. I would have him just ahead of Phil Taylor and Manchester United. So impressive. Thoughts?"

Sho_Rahman on Twitter: "Nadal is going to destroy Murray tomorrow.....just wonder how many games Murray can win"

1618: It will be interesting to see what Rafa says in the press conference regarding his outburst. He refuses to expand on his feelings about the umpire call saying that he will need his Spanish translator! The incident seemed to inspire Rafa though.

1615: Does Nadal ever stop smiling off the court? Words after the victory which secured his semi spot: "It's a very important victory. Congratulations to Tomas for the season. I have played every day a little better and today was a great match against a very difficult opponent. The umpire was wrong - but maybe it was me!" (Regarding the challenge and the overrule at the end of the first set)

1611: A slightly disappointing second set but overall, a brilliant match that had pretty much everything. So it's Nadal v Murray. Federer v Djokovic/Roddick. That last round-robin match is on from 2000 GMT. More permutations in a bit. Roddick needs to win in straight sets. And that's a fact. Interesting.

Berdych 6-7 1-6 Nadal
Oh my lordy. Nadal edges 30-15 ahead and Berdo lobs him, Nadal storms to the back of the court and surely not a hot-dog? He makes good connection, the ball is flying over but kisses the top of the net and just goes out. Some late fireworks. Brilliant. And that's it. NADAL WINS. So that cork can be out-popped again. He'll be up against Murray in the semis. Berdych is out.

Berdych 6-7 1-5 *Nadal
Berdych has a mountain to climb and he trails 0-30. He gets one back and comes into the net looking favourable before Nadal's spin shudders off his racquet and Berdo plays long. 15-40. Last chance saloon for the world number six? Nadal takes it and he's now serving for the match.

Anonymous but still called Liz!, via text 81111: "I wld love Nadal 2 win the finals, but life is funny..Murray was down and out but has been given a lifeline. He can beat both Nadal and Feds, which he has done b4, and take the trophy. I hope not though VAMOS RAFA!"

Berdych* 6-7 1-4 Nadal
A bit of a struggle this for Nadal and it goes to deuce with Berdych fighting for his life with a whole box of stunning defensive shots from the back. Brilliant. Nadal is not amused. Nadal's first serve firing on all 20 Spanish cylinders and he takes the game by following up with a thunderous forehand. The Nadal train is rumbling and not short of some noise.

Berdych 6-7 1-3 *Nadal
Nadal looking a bit grumpy as Berdych continuing to get plenty of success at the net. Time for a flurry of crucial deuces. BBC Two may have said goodbye but coverage now on the Red Button. The game drags into its eighth minute. Tense and very quiet inside the O2 with everyone watching Berdo's serving arm warming up. He then plays a corker inside the baseline to get the advantage. From the beauty to the beast. He ploughs one into the net and that's not clever. More deuce. And he'll be regretting that as he loses two points in a row, the latter being a miserable dribbler into the net with an attempted dropshot. Shame. Big game to lose.

Jack and Liam, two unhealthily bored, cold and sad students in manchester, via text 81111: "Amusing hearing Andrew Castle and Tim Henman complaining about 'confusing mathematics' in the round-robin format. As two engineering students we don't completely agree that something other than counting in tennis makes it confusing"
Shouldn't you be in lectures or knocking up a spaghetti bolognaise? Joking apart, (and i was joking) - great to have you onboard. I loved my bolognaise. Can Berdych serve up a spaghetti comeback this afternoon?

Berdych* 6-7 1-2 Nadal
A vicious array of shots by Nadal and the game is soon waving goodbye. Any way back from Berdo in this one? BBC two also waving ta-ta but don't forget BBC Radio 5 live sports extra and woohhh there! Don't even think about leaving this live text. Current thoughts?

Piers Newbery on Twitter: "Great first set goes to Nadal on tie-break, most interest on his furious outburst though, very unusual. And I learned the Spanish for socks."
An obvious fact is demanded after such a tweet. El sockos?

Anonymous, via text 81111: "If Nadal goes on to win this tournament, as I suspect he will, he will have rubber-stamped his utter dominance in the men's game. A ferocious will to win"

Berdych 6-7 1-1 *Nadal
Berdo needs to steady the ship but he's wobbling at 30-30 and then he plays it too long to hand Nadal a break point. The Czech stares at the court in disgust. A kicking serve and he gets it to deuce. But he pulls it out of the bag after trailing 0-30. Nice.

1535: For anybody cracking open the Friday champagne in anticipation of a Murray v Nadal semi, you need to get the cork back in. There is just one scenario where Nadal will not finish top of Group A. But it still exists. Berdych comes back to defeat Nadal in three sets and Djokovic defeats Roddick later in two sets, meaning Djokovic wins group and Nadal qualifies in second spot. Confused?

Berdych* 6-7 0-1 Nadal
Has Nadal taken his foot off the gas? His serve goes to deuce as the crowd - and me - collect their thoughts after a breath-taking opening set. A brilliant point by Berdo gets it back to deuce. Fabulous from both though as they twist and turn, getting themselves out of trouble from the back, but Berdo is fighting like a snarling dog. He wants to be playing over the weekend. Nadal just sneaks it.

Berdych 6-7 Nadal
TIE-BREAK. Oh boy. This is immense. Berdo fighting for his life. Can Berdych take a set off Nadal for the first time in four years? An early break and Nadal leads 2-0 then 3-1. Berdo's first serve success rate is 39% says Tim Henman. Two in a row get him out of trouble, for now. Nadal leads 4-2 as they change ends. Can you feel the tension? Could you cut it with a large wooden spoon? Oh Tomas. A double-fault gives Nadal four set points. One saved and he's now got two serves for the set. The roof will be raised in a few moments I feel. And the set's wrapped up by a stunning dipping forehand. And that means Nadal is through to the semis. Think he's happy? A wonderful set full of twists and turns, temper-tantrums and brilliant tennis. Berdych still desperately needs to get something out of this match. Even if it's one set.

Berdych* 6-6 Nadal
Interesting conversation between Rafa and the umpire in Spanish. The umpire calls "long" after Nadal raises his arm to challenge the call. Berdych then challenges and replays show it's in. It should be a replay of the point but the umpire hands the point to Berdych. Nadal is steamingly unhappy. Nadal then blasts a forehand back and those guns are exploding. I fear for the immediate air around the Spaniard because he pulls out a massive air-punch. Anyone think Rafa is pumped? 15-30 to 40-30. The script writers would have Nadal now winning the next point for the game, the crowd go bonkers, the Spanish flags wave, cue the music as Nadal punches the air again. You'd be wrong. Berdo plays a cracker and it's deuce. What a game. And the game's now over. That game has worn me out. Brilliant. Drama-rama.

barnoit on Twitter: "Is it just me, or does purple-clad Nadal look not unlike Ben Stiller's character in "Dodgeball?"
I'd love to give you a big fat YES because I love the character, but I can only give you 4/10 for that one. Thanks for the effort though.

Berdych 6-5 *Nadal
Nadal plays a cute dropshot trailing 30-0 but Berdo's having none of it - he steams in and blasts the ball straight at his opponent and it lands in. I think the ball must have gone straight through Nadal? Just a blur. Great work-rate from Berdo. 40-0. It's Nadal's time to raise his work levels and Berdo stares at the roof and wonders just how Nadal has back to within a point. Don't fear Tomas. WALLOP. Worthy of the capital letters as Berdo batters the ball back to take the game. Stunning.

Berdych* 5-5 Nadal
And those butterflies may well be doing a Majorcan jig right now as Berdo takes the first point. Time for the Nadal grunts and it's a phenomenal rally. Berdo is on top of it, totally, he comes in on a good approach and Nadal somehow plays a forehand at Berdo's toes and he makes it 15-15. That's a massive. Football pundits talk about six-pointer matches. That point must have been worth three! Time for Nadal to come in and he plays a smart winner to lead 40-15. Replays emphasise just how much spin the Spaniard is applying to these balls. Incredible. And it's all level again. Interesting few minutes coming up.

FlynnS in London, via text 81111: "On the train up to the 02 to see Roddick take on the big Serb! I'm supporting Roddick, my granny the Serb! This could be war!"

Berdych 5-4 *Nadal
Nobody thought Berdych was going to buckle there did they? A few errors from Nadal and now he's serving to stay in the first set. Remember - Nadal just needs to win one set today to go through. If he loses this opener though, there'll be a few Spanish butterflies dancing around under his six-pack. (In his tummy that is)

1455: On BBC Two, Tim Henman on his experience of hitting with a 17-year-old Nadal: "At first I thought, 'This is just ridiculous, you can't try and hit the ball that hard without making mistakes all over the shop'. Forty-five minutes later, he had beaten me 6-1 and I thought 'Maybe you can'."

Berdych* 4-4 Nadal
11 winners so far from Nadal and his 11th is a sublime back-hand slice that kicks away low and savagely. At last, a comfortable service game. Wins it to love. This is where the best players crank up the gears. How many gears does Rafa have would you say?

Berdych 4-3 *Nadal
"Berdych really doing a great job but I'd like him to do better with his serves," says Tim Henman on BBC Two. He goes 30-0 up and looks good in the next rally before his return from the back just drifts out. Mmmmm And then a double-fault gets it to 30-30. He'll need to cut those out. Berdych is all smiles - a sign of resignation really - as Nadal plays a cross-court winner when he was looking dead and buried. The scowl count increases once more. But Berdych holds on. New balls are on the way. No better time to play Cameo's 'Word up'. If only we had a few extra minutes to talk about those boys' fashion crimes.

deksta on Twitter: "Tomas has nothing to lose - that's his biggest weapon"

Berdych* 3-3 Nadal
A fairly comfortable service game so far and Nadal takes it to 40-15 with the shot of the game - a crunching forehand into the corner. Berdo goes long and it's all level again.

Jo in London, via text 81111: "I wonder why players wear bright colours. It can only be easier for their opponents to spot them on the court. Does any player know the art of camouflage?"

Berdych 3-2 *Nadal
Signs of a slight wobble by Berdo as Nadal edges 15-30 ahead. More Spanish scowls (happy determined ones) as his double-handed back-hand flies back with Berdo left flat-footed and helpless. Two break points. Nadal then steams into the net eyeing the game but Berdo is having none of it as he plays a corker down the line which Nadal can only flap at. Brilliant. Great response from the Czech though with a dose of solid serving - first serve and second - gets him four points in a row and the game. Top fightback and the crowd love it.

Berdych* 2-2 Nadal
Nadal is on it and he's on it from the back with another crushing back-hand winner to take it to 15-15. NEWSFLASH - the ATP website reveals that Nadal's shirt is...wait for it.... purple. No more shirt mentions. Promise, unless nudged by you. A great rally to finish the game as Berdych just goes wide. A box of tricks being dished up by both. Only thing missing is the dropshot so far.

Berdych 2-1 *Nadal
Berdych looking comfortable at 30-15 and looks good again at the net but Nadal shuffles his feet and plays a disguised pass to Berdo's right. Nice again. A high level of tennis already from both. His service is too strong though as Nadal struggles with one that flies off the back of the line. Berdo's nose in front.

1424: On BBC Two Andrew Castle says: "That's the way, take it early and move on in. He is already playing better than he did in the Wimbledon final."

Berdych* 1-1 Nadal
Woh there Tomas. Great opening to this Nadal service game. He gets Rafa on the run, pushing him from side to side four times, before aggressively coming in and swiping the ball away. Two break points. The crowd don't know whether to cheer or go 'oooh'. I'm sat here definitely doing the 'ooooh' option. Nadal scowls after an ace gets him back to deuce. For all his off-court smiles, he is not a man to be messed with. Henman describes Nadal as "electric" and the world number one nabs the game. Great intentions from Berdych though. Top game.
* denotes NEXT to serve

Smarties1093 on Twitter: "Nadal's biggest weapon is that dodgy outfit. Maybe's he's actually playing really bad."
The debate will rumble on with Nadal's outfit. Is it magenta? Is it raspberry? Do you care? Do clothes matter?

Berdych 1-0 *Nadal
Berdych - sporting his usual lowkey all-white outfit - grabs an early ace to lead 30-15 and then stoops low to play a cracking forehand winner down the line. Nice. Nadal goes wide and that's first blood to the world number six.
* denotes NEXT to serve

1414: So with Nadal surviving losing the first set to Andy Roddick he now stands on the edge of progressing. He needs a set today against Berdych. The only way of the Spaniard being dumped out of the Finals is he loses in straight sets this afternoon and Djokovic defeats Roddick in three sets in the later match at 2000 GMT. Surely not? How can Berdych win? Tim Henman jokingly suggests Berdych should knock over Nadal's bottles courtside to put him off. Just a few seconds away now. Berdych NEEDS to win. Keep your thoughts coming in. Berdo to serve. Let's go. Have a great afternoon by the way.

jjjlee1988 on Twitter: "Hope it'll be a good one, to make up for my missing Murray vs Ferrer last night."

1409: The pair are out there warming up. Some pre-match thoughts. Berdych says: "It's a nice match to play. I'm really looking forward to it and we will see how it goes. I will try to play aggressive and be focused on the first points and try my best." While Nadal says: "I started playing the tournament so-so but I played a good level against Djokovic but every day is different and Berdych is difficult. I is difficult to stop him and I will need to play well."

1406: Nadal leads head-to-head against Berdych 8-3 with the Czech winning three of their first four meetings. It's all been downhill since. Nadal is 7-0 up since the start of the 2007 season and has not even lost a set against the Czech in over four years now. The last time they met was Nadal winning in the Wimbledon final. Has Berdych got any chance?

1400: Enough of my chat. I'd like your thoughts. I won't even charge you for them. Nadal should cruise through today no? More on the permutations and stats in a mo. Tweet me @bbcsport_mark, text me on 81111 (UK) or +44 7786200666 (worldwide) with TENNIS before your message, or join the banter on 606.

1356: Afternoon. Anybody fancy a diet of fat-free, low-carbs tennis? Caution - this meal may contain some traces of nuts. You have been warned. Nadal v Berdych. All for a spot at the semi-finals in the World Tour Finals. In or out?