Sheffield (England), May 3 (IANS): Three-time Crucible winner Ronnie O'Sullivan is a hot favourite to claim a fourth World Snooker Championship title after he rallied to beat Australia's Neil Robertson 13-10 in quarterfinals.

The English veteran, who won World titles in 2001, 2004 and 2008, delivered a thrilling comeback victory when he overturned a 3-5 deficit to lead Robertson 9-7 after the second session with a six-frame streak Wednesday.

Robertson, the 2010 World champion, threatened a comeback of his own after he narrowed the gap to 10-12 with breaks of 89 and 77 but to his disappointment conceded the last frame.

"My game is aggressive and I don't mind leaving people chances as long as I'm cueing all right," O'Sullivan was quoted as saying by Xinhua.

"Neil's had a great tournament, he's been fantastic and he's had another good season," said Robertson about the 36 yeal-old's game.

O'Sullivan will play Welshman Matthew Stevens in the semi-final, who thrashed his compatriot Ryan Day 13-5, under the best of 25 frames.

The other semi-final will be played between Stephen Maguire of Scotland, who defeated Stephen Hendry 13-2 and Briton's Allister Carter, who saw off another Welshman Jamie Jones 13-11. Hendry who announced his retirement immediately after the loss has been the youngest snooker world champion at age of 21 with seven world championship titles to his credit.

Quarterfinals (Best of 25 frames):

Allister Carter, England, bt Jamie Jones, Wales, 13-11
Ronnie O'Sullivan, England, bt Neil Robertson, Australia, 13-10
Matthew Stevens, Wales, bt Ryan Day, Wales, 13-5
Stephen Maguire, Scotland, bt Stephen Hendry, Scotland, 13-2 (on Tuesday)

Semifinal lineups (Best of 33 frames):
Stephen Maguire vs Allister Carter
Ronnie O'Sullivan vs Matthew Stevens