Ronnie O'Sullivan raises his game to claw back John Higgins lead

Ronnie O'Sullivan hoped John Higgins would bring the best out of him and that was how it proved as their Crucible quarter-final got under way.

The experienced pair, both 35, finished level at 4-4 after an absorbing opening session at the Betfred.com World Championship, with Higgins left to regret a missed black off its spot in frame seven when he was well set to open a 5-2 lead.

Offered half a chance to win the frame, O'Sullivan took it with an exquisite 89 break and followed up by rattling in 105 to bring the session to an end. He had trailed 2-0 and 4-2 but showed resilience to fight back on each occasion.

Higgins had a total clearance of 121 in frame six, probably the easiest of his career after the balls were spread evenly around the table after a drawn-out safety battle between two players who prefer to attack.

Higgins was relishing the contest with O'Sullivan which is ideally balanced heading into tomorrow's morning and evening sessions. "It's always a great occasion, wherever you play him. He's got the Jimmy White and Alex Higgins factor, the crowd are on his side and that generates a buzz that you love playing in," Higgins said.

"Playing O'Sullivan anywhere probably generates the same buzz as playing in a final against most other people."

Nobody would have been less surprised than Higgins by O'Sullivan's stunning finish to the session.

Indeed, Higgins has been far from shocked to see O'Sullivan, almost with the flick of a switch, hit form in Sheffield after a mostly dismal season. "No, of course not," the Scot said. "He's so talented that he can do that."

The pair, both three-time former world champions, were pitched together so early in the tournament because of O'Sullivan's slide to tenth in the rankings, affecting the seedings.

While O'Sullivan pitched up in Sheffield having not won a match in a ranking event since September, Higgins has carried off the UK Championship and Welsh Open titles since his return in November from a six-month ban for not reporting an approach by a journalist to lose frames for money.

"John's given everyone half a season start and still won more than everyone else," O'Sullivan said. "He's a class player, he's been the best player in the world for the last three or four years probably. I've got great respect for John's game."Higgins surged in front with breaks of 53 and 66 in the opening two frames, but runs of 69 and 41 brought O'Sullivan level.

O'Sullivan should have gone 3-2 ahead, but missed a red to a top pocket when on a run of 28, and later missed a frame-ball brown.

After mopping up everything on the table in the next frame it seemed Higgins was in charge, only for O'Sullivan to delight the crowd as the session drew to an end.

The recovery said a lot for O'Sullivan's ambition in the tournament.

He is seeing early results from his work with sports psychiatrist Dr Steve Peters and, after seeing off Shaun Murphy in the second round, he intends to stay around for the duration.

Mark Selby was favourite for the title as he headed into his quarter-final against China's Ding Junhui, who last night came from 12-9 behind to beat Stuart Bingham 13-12 in the second round.

But Selby must come from behind tomorrow after Ding opened a 5-3 lead over the Leicester potter.

Selby had a tournament record of six centuries in his last-16 win against Stephen Hendry and began with another today against Ding, 124 in the first frame.

However Ding then strung together four in a row, featuring breaks of 58, 53, 63 and 65. Selby made it 4-2 with runs of 51 and 87, but Ding guaranteed himself an overnight lead with 77 in frame seven. Selby finished with 74 to stay in the hunt.

Tonight Judd Trump was returning with a 7-1 lead for the second session of his match with 2006 champion Graeme Dott, while Mark Williams headed Mark Allen 5-3 as they resumed. Allen finished their morning session with back-to-back centuries.