SHEFFIELD, England, May 2 (Xinhua) -- Three-time Crucible winner Ronnie O'Sullivan became hot favourite to claim a fourth title of the world snooker championship after he rallied to beat Neil Robertson 13-10 on Wednesday in a "final before the final" to get a last-four berth.
The English veteran, who won the world titles in 2001, 2004 and 2008, delivered a thrilling comeback victory when he overturned a 5-3 deficit to lead Robertson 9-7 after the second session with a six-frame streak.
The Rocket then never looked back and held his nerve to finish the job, knocking out the Australian top player with a three-frame advantage.
Though losing the match, Robertson, the 2010 world champion, threatened a miraculous comeback after he narrowed the gap to 10-12 with breaks of 89 and 77 but only saw his opponent in a strong mind to seal the victory.
The duo's offensive-minded styles made it an exciting and high quality match and was worth the nickname billed by some as the 'final before the final'.
"My game is aggressive and I don't mind leaving people chances as long as I'm cueing all right," said the 36 year-old winner.
On his opponent, the Rocket added: "Neil's had a great tournament, he's been fantastic and he's had another good season."
O'Sullivan will play against Matthew Stevens, who thrashed Ryan Day 13-5, under the best of 33 frames in the semifinal.
The other last-four clash will be played between Stephen Maguire, who beat Stephen Hendry 13-2 before the "snooker king" announced his retirement, and Allister Carter, who saw off Jamie Jones 13-11.
The world championship, the yearly biggest tournament of a snooker season, has been held at the Crucible theatre since 1977.