Frame 28: O'Sullivan plays a great safety shot to snooker Swail behind the yellow on its spot, and as a result opens the frame with a break of 39 - carelessly missing an easy red.

Swail responds, opening the pack from an early black, reaching 65 with only one red left on the table - tight on the cushion.

Swail attepts to double the red with safety in mind and misses.

O'Sullivan produces a fine snooker and as result wins a free-ball and an opportunity to win a place in the final.

The "Rocket" obliges and takes the match 17-11.

Frame 27: Swail gets the first clear opportunity of the frame after O'Sullivan misses a half-chance.

After compiling 54 the Northern Irishman falls the wrong side of the blue and as a result leaves a missable red - he did, but O'Sullivan didn't take advantage and Swail was immediately back in to take the frame with his second half century of the frame.

Frame 26: The "Rocket" miscues a simple black after compiling 38 points from his first visit to the table - Swail left a long red from his break.

Swail hits back, equalling the scores, but takes on a tricky red and misses.

O'Sullivan needs no second invitation and wins the frame with a clearance to the black.

Frame 25: A relaxed but determined Joe Swail produces a scintillating 114 break after potting a long red left early on by Ronnie O'Sullivan.

The sixth century of the match ended when Swail was set to better his own highest break of the tournament - 140. A tricky yellow rocked in the jaws of the pocket as the arrears were reduced to five frames.

Frame 24:
The unstoppable O'Sullivan ends the night with a flourish as he takes the final frame of the session 84-9, with a brilliant 84.

The exocet now needs just two frames when play resumes at 1430 BST on Saturday, to reach his first world final.

Frame 23:
Swail refuses to go down without a fight as he fires in a quality break of 138, defying his nerves and reducing the deficit to 14-9.

It is the 31-year-old, 16th seed's third ton of the tournament.

Frame 22:
Swail pulls a frame back and ensures the match goes into a final seesion on Saturday afternoon. He produces a 52 clearance and keeps O'Sullivan in his seat as he takes the frame 18-105.

It seems, however, that he is only delaying the inevitable.

Frame 21:
O'Sullivan moves a step closer to his first World Championship final with a tradmark break of 79. Swail can only watch from his chair, a forlorn figure, as the Rocket goes about his business.

A scoreline of 79-77 gives O'Sullivan a 14-7 lead.

Frame 20:
Swail's hopes of a revival come to a bitter end as the Rocket comes from behind to take the frame 61-58, going into the mid-interval break with an ominous 13-7 lead.

The shock of the frame sees O'Sullivan come off the top cushion and down the table, leaving a red hanging over the middle pocket.

Frame 19:
The Comeback King Swail keeps his nerve and wins the first frame of the session with a composed clearance, which gives him the frame 59-57.

However, Swail still has an awful long way to go.

Frame 18:

O'Sullivan takes a 12-6 lead with a stunning century break in a frame which lasts just over 10 minutes.

He could have equalled the highest break of the tournament so far - his opponent Swail's 140 - and claim a share of the �20,000 prize, but for a bad position on the a final black, which he then misses.

Frame 17:
The first frame of the third session sees both players miss several frame-winning chances before O'Sullivan eventually takes a scrappy frame 62-59.

It's a frame Swail can't afford to lose, but he misses a vital pink and O'Sullivan capitalises by calmly rolling it in before sinking the black.

Frame 16:
Swail takes the final frame in a captivating session of snooker. A break of 37 puts him in control - O'Sullivan responds with a 44 - but a rare miss allows the Comeback King to take the frame with an assured clearance.

The match, which many believed would be over in three sessions, is now perfectly poised for Friday evening's session. O'Sullivan, playing brilliant snooker in patches, remains the favourite to book his place in Sunday's final but Swail will be anxious to stop him.

Frame 15:
The stubborn Swail refuses to surrender to the Rocket's deadly potting, clinching the 15th frame with a 92 clearance.

The match is developing into a gripping contest, with O'Sullivan slightly fazed at Swail's steely determination. The plucky Irishman, nicknamed the comeback king after his miraculous recoveries earlier in the tournament, is scoring heavily when given the chance.

However, it will take an almighty effort from Swail if he is to recover from 10-5 down against snooker's most gifted cue master.

Frame 14:
O'Sullivan moves a step closer to the finish line, winning a tight frame and knocking in another half century on the way.

With 25 points left in the table, O'Sullivan played a serious contender for shot of the championship, thundering in a long green before screwing back in sensational fashion for the brown.

Even Swail applauded The Rocket's effort - cue power at its very best.

Frame 13:
O'Sullivan returns from the mid-session interval in rampant form, knocking in a 51 break to move 9-4 ahead.

Frame 12:
O'Sullivan punishes Swail after the "Outlaw" misses an ambitious long red. But a quick-fire break of 44 isn't enough for the Rocket as Swail prevails to win the frame 75-44.

Frame 11:
Swail finds his feet in the 11th frame, galvanising a scrappy frame with a break of 51 to pull himself back to just a five-frame deficit.