Two-time snooker world champion Ronnie'Rocket' O'Sullivan, pictured in 2000,fought off fierce challengefrom Australia's Neil Robertson who came back from 6-2 down to level at8-8 at the end of the afternoon. (AFP, FilePhoto)

SHEFFIELD, England, May 1 (Xinhua) -- Ronnie O'Sullivan, John Higgins, Allister Carter and Mark Selby all reached the quarterfinals after winning their respective matches at the world snooker championship here on Monday.

O'Sullivan fought off fierce challenge from Australia's Neil Robertson who came back from 6-2 down to level at 8-8 at the end of the afternoon.

But O'Sullivan dominated the evening session and won 13-10.

O'Sullivan will take on Higgins in the last eight. Higgins advanced with a 13-4 victory over Ireland's Fergal O'Brien.

Qualifier Selby produced an impressive display to knock out former champion and last year's runner-up, Peter Ebdon.

Selby, who beat Stephen Lee in the opening round, compiled five centuries on his way to a 13-8 victory.

The other players through to the last eight are Matthew Stevens, Shaun Murphy, Stephen Maguire and Anthony Hamilton.