However, after a 13-10 quarter final win against Neil Robertson on Wednesday night, O’Sullivan is overwhelming favourite to claim a fourth World Championship, with odds of 4/6 (Paddy Power free bet) about the Rocket.
The number 14 seed comes up against the number 15 seed in the semi-final, with Matthew Stevens having won ten frames on the bounce against compatriot Ryan Day to secure a 13-5 quarter final victory on Wednesday.
We shouldn’t forget that Stevens has reached the final on two occasions at The Crucible and he is as big as 12/1 (Bet Victor bookmaker) to go one better this time around, with the Welsh Dragon having previously beaten Barry Hawkins and Marco Fu.
Meanwhile, the other semi-final will see Ali Carter face Stephen Maguire, with the former knowing what it takes to reach a World Snooker Championship final. The Captain actually reached the final in 2008 when losing to O’Sullivan and it could be the same again this year.
However, On Fire Maguire looks very solid and wiped the floor with Stephen Hendry in the last eight, conceding just two frames. The Scot is on offer at 10/3 (Ladbrokes) to win his first Crucible title.
Ronnie O’Sullivan v Matthew Stevens
These two players have never met at The Crucible which is quite a stat when you consider the pair have both reached the business end of the World Championship on several occasions.
O’Sullivan will be playing in his 9th semi-final in Sheffield, although it is his first appearance in the final four since 2008 when he won the tournament. The bookies expect him to make another final this time around, with a best price of 1/4 (Stan James bookmaker) available about the Rocket proving too strong for his opponent.
Stevens claimed after his win against Ryan Day that being the underdog would suit him, although he will surely have his work cut out against O’Sullivan based on the way that the Londoner is playing.
The Welsh Dragon will be looking to take advantage of any wobbles and can be backed at 4/1 (Boylesports) to upstage the Rocket, although this could be a comfortable win for the favourite and you can get odds of even money (Paddy Power free £100 bet) to win with a -5.5 frame handicap.
Stephen Maguire v Ali Carter
There will be a real clash of personalities on Thursday afternoon, with a laid-back Stephen Maguire facing an intense Ali Carter for a place in the World Snooker Championship final.
Maguire has been relatively untroubled en route to the semi-finals, having beaten Luca Brecel, Joe Perry and Stephen Hendry to reach this stage of the competition and the number eight seed is warm favourite to win this clash.
The man known as “On Fire” can be backed at 1/2 (Betfred bookmaker) to beat the Captain, although perhaps that’s an overreaction to Maguire’s 13-2 win over Hendry which was largely achieved thanks to the latter’s poor performance.
Carter has had two tough matches to reach this stage of the World Championship and that would be the main concern for the Essex potter, who knocked out Judd Trump in the second round thanks to reeling off four frames on the bounce to win 13-12.
Jamie Jones then gave the number 13 seed a tough game in the last eight, although Carter has shown the ability to scrap his way to victory and perhaps has a slightly stronger mental resolve than his opponent.