Ronnie O’Sullivan completed a tremendous clearance to beat Mark Selby and book his spot in the Masters semi-finals, yesterday.

O’Sullivan is back on the big stage after eight months away and battled to a 6-5 victory over Mark Williams in round one.

The five-time world champion was still not happy with his form following his 6-3 win against Selby, but those watching were certainly impressed.

O’Sullivan was never behind at Alexandra Palace, winning the opening frame with a 63 break before Selby pulled level.

Three more breaks over 50 helped O’Sullivan into a 3-1 lead and a break of exactly 100 put him 4-2 up at the interval.

Both men knew the seventh frame was crucial and made mistakes as a result, but it was O’Sullivan who crossed the finish line.

Selby mounted a fightback by winning the eighth and looked poised to make it 5-4 when he compiled a break of 70.

But O’Sullivan cleared the table with a 73 and will play either John Higgins or world champion Stuart Bingham in the last four.

O’Sullivan said: “I don’t feel great but you’re not going to win this tournament by playing negative, playing bad. I need to try to find something.”