Ronnie O'Sullivan today booked his place in the second round of the world championship at the Crucible in Sheffield. Resuming against Chinese teenager Liu Chuang with a slender 5-4 lead, O'Sullivan won three of the afternoon's first four frames to lead 8-5 at the mid-session interval.

The two-time world champion then took two more frames after the interval to secure his place in the last 16 and a clash with another former champion, Welshman Mark Williams.

O'Sullivan was in a relaxed mood, playing a number of shots left-handed and then deliberately fouling on the last red with the 11th frame already secure by sprawling across the table with both feet off the floor.

The 17-year-old Liu, was first among the balls in the next frame and a run of 53 ultimately proved enough to take it after O'Sullivan missed the brown when attempting to clear up. O'Sullivan then took the 13th frame with a break of 65 and looked to have ended Liu's hopes of creating arguably the sport's biggest upset.

He also took the 14th frame despite breaking down on a break of 56 as he attempted an outrageous positional shot to keep alive his chance of a 147 maximum. And the Rocket duly completed a 10-5 victory in the next, clearing up the last red and the colours to take the frame 70-59.

The second round was already under way on the other table, Mark King and Peter Ebdon locked at 2-2 at the mid-session interval.

King, who defeated last year's beaten finalist Mark Selby in the first round, took the opening frame with a break of 81 and also led 2-1 - but Ebdon battled back to level in what was already shaping up to be a tight affair.