Joe Swail tempted fate this week. In his tempered celebration following the defeat of his friend Patrick Wallace in the quarter-final, Swail spontaneously offered an opinion on how he should approach his semi-final match against Ronnie O'Sullivan.

"I know I'm going to have to play to a very high standard consistently, not 6-2 down or 80 down. None of that nonsense. Ronnie is the type of player that will just finish you off in no time at all," said Swail.

No doubt the Belfast player is now reinforcing himself from the negative rebound of his comment as he finds himself exactly where he didn't want to be, 6-2 down after the first session.

O'Sullivan, something of a confused soul and the closest thing snooker has to a stroppy rock star, and Swail, the chummy Irish lad breezily thumping his way through the draw, form contrasting images. But both feed off momentum, and both can swing in form over a couple of hours. That may give Swail some little comfort to a sticky start.

O'Sullivan, with his game in pristine condition, is perhaps more precariously aware of this Achilles heel as he seeks to distance himself from the player with whom he is most often compared, Jimmy White. White, a non-qualifier this year thanks to Dublin's Michael Judge, will always be remembered as the best player never to win at the Crucible, a moniker O'Sullivan hopes to avoid. Rather he seeks to become the first English player since John Parrott 10 years ago to win the title.

Both players also enjoy the quick fix on the table. Wallace, for all of his guile and composure, sought a snooker against Swail in the quarter-final with just four colours on the table. The improbable effort naturally ended in failure, but the passage took 20 minutes to conclude. It was a grinding attitude that neither Swail nor O'Sullivan are inclined to employ.

The first session offered evidence of how the match may well resume, although, ominously for Swail, O'Sullivan appears more measured in his play and was not prepared to go duelling with his opponent on long shots with short odds of success.

The 25-year-old O'Sullivan hinted that he would adopt a more reclined approach before the semi-final had even started.

"I've never felt so relaxed. In between matches I've been getting away and chilling out. I won't pick my cue up until half an hour before the semi-final," he said, not long after Peter Ebdon had offered a eulogy with the now famous Mozart connection.

Ebdon is not the only one prepared to say O'Sullivan is in the . . . er, right mood to win it this year, and although the fourth seed has never been beyond the last four at here, William Hill have him at 6 to 5 to win the title and 1 to 6 to beat Swail.

But it was Swail who hit a breathless 107 in a dream start. O'Sullivan then replied with 73 to level. On a frame-winning run in the third, O'Sullivan carelessly allowed his waistcoat to brush a red on the cushion and, mercilessly, Swail came in to clear for 2-1.

But that was the end of it. Breaks of 62, 58 and 70 brought O'Sullivan to 5-2 before critically he nicked the last frame to leave Swail sleeping overnight on the irritating fact that it could so easily have ended a more manageable 5-3.

Matthew Stevens, who earned Stephen Hendry's approval as having the best cue action in the world in the quarter-final round, opened his match against John Higgins just as Swail had done.

From the blocks Stevens hit 100, the 41st of the competition and his fifth. But Higgins soon turned it around and moved into the gear that had Ken Doherty struggling for so long in the last round.

The second-seed Scot claimed the next three frames in succession. The fourth game, in particular, showed Higgins in championship-winning form, with several audacious pots keeping him on the table and Stevens firmly seated. Higgins went into the mid session interval 3-1 up and very much the player dominating the table.

That continued when they resumed. Stevens pulled back a frame for 3-2 before the 25-year-old catapulted ahead with the next two games.