Davis stuns Robertson in 82-minute final frame as O'Sullivan eases through

Five-times world champion Ronnie O'Sullivan had no such problems as he completed a 4-0 win over Gloucester's Robert Milkins in a match that lasted only 55 minutes. O'Sullivan has won 34 frames and lost only five in all his career meetings with Milkins.

He was never under any real strain as knocks of 72, 64 and 68 carried him through with minimal fuss as he chases the £100,000 first preize.

O'Sullivan's reward is a quarter-final meeting with Scotland's Graeme Dott, who completed a 4-3 win over China's Liang Welbo.

"I'm pleased to get the win - I played better than I did in my first game because I've had a couple of days practice," said O'Sullivan.

"I've done more practice in the last two days than I did in the month before.

"I'm happy to have won two matches because this is a great event at a great venue. When the players come to an event like this they naturally want to produce their best snooker.

"To have the chance to play another match here - I feel like it's Christmas all over again. I'm like a kid in a sweet shop."

World champion Mark Selby was a surprise 4-2 loser to Martin Gould, who enjoyed breaks of 113 and 67.

"It's a great result for me and now I've got to produce that again in my next match," said Gould.

"I never worry about who I'm playing, I just go out there raring to go and do my job. I've got a day off tomorrow so I think I'll find somewhere to play some cribbage and dominoes."

World number two and former world champion Robertson had taken a 3-1 lead in the match, but Davis hit back with breaks of 81 and 63 to force a decider.

And what a decider it proved to be, coming in just 11 minutes short of the record length for a televised frame of snooker - the previous record being the 93-minute epic between Shaun Murphy and Dave Harold at the 2008 China Open.

A series of safety exchanges saw both men pick up points here and there without getting a chance to take control of the frame, and the match eventually came down to the colours - where Robertson claimed brown, blue and pink to look on the verge of victory.

But he ran out of position on the black and was unable to pot it - and Davis subsequently managed to crack in a lengthy effort to earn a quarter-final against Stuart Bingham.

"It was just one of those frames which takes a long time," said Davis.

"It could have gone either way in the end - throughout the frame there was never a lot in it.

"It's just great to win, beating Neil is tremendous. It's got to be one of the best victories of my career.

"I was always going to take that final black on. I nearly doubled the black the shot before when it was on the cushion. I said to myself if I have a genuine pot, there's no way I'm playing safe."

Bingham's quarter-final spot came courtesy of a 4-2 win over Matthew Selt, while Mark Williams beat Ricky Walden 4-3 thanks to good breaks in the final two frames.

Williams will play Judd Trump in the last eight, Trump having beaten Joe Perry 4-2.

Later Peter Ebdon beat Stephen Maguire 4-1 to progress.

1pm: Mark Davis v Stuart Bingham

Not before 2pm: Martin Gould v Stephen Maguire or Peter Ebdon

Not before 7pm: Ronnie O'Sullivan v Graeme Dott

Not before 8pm: Judd Trump v Mark Williams