Mark Allen became the first player to ever make a 146 break at the Crucible as he moved ahead in his second-round clash against Mark Davis.
The 24-year-old Northern Irishman lost the opening two frames to Mark Davis but rallied well to go into the mid-session interval level at 2-2.
Allen, a semi-finalist at the Betfred.com World Championship last year, edged ahead for the first time and then had an outstanding chance of a 147 maximum in the sixth frame.
After six reds he lost position by a fraction and had to take pink rather than black, but as if to prove a point to himself he went after the 146 and brilliantly reached his target.
Whereas a maximum would have brought him prize money of £157,000, Allen had to settle for being the front-runner for the highest break prize, which pays £10,000.
He also led 4-2, with two more frames to be played today before two further sessions tomorrow.Although 146 breaks are more rare than 147s, Allen has made two, with his first having come in qualifying for the UK Championship in 2007.
There have been nine maximum breaks in World Championship history, with Stephen Hendry recording the most recent during his quarter-final against Shaun Murphy at last season's tournament.
Allen finished the session with a 5-3 advantage, Davis winning the eighth frame to stay in touch ahead of the resumption tomorrow morning.
Meanwhile, Murphy set up a second-round meeting with China's Ding Junhui by scrambling over the line this afternoon against Gerard Greene.
He almost made a complete mess of the session though, and was clearly relieved to polish off a 10-7 win.
Greene trailed 8-1 overnight and Murphy soon made it 9-2.
But Greene managed to win six of the first seven frames of the session, including one when he required snookers.
The Kent-based Northern Ireland left-hander had Murphy in a touch of trouble when he fired in a break of 92 to narrow the gap to 9-7.
But a chance came Murphy's way early in the 17th frame and he calmly recorded a break of 87.
Had Greene managed to complete the comeback, it would have matched the greatest recovery in a first-round Crucible match, Nigel Bond having beaten Cliff Thorburn from 9-2 down in 1994.
Murphy, 27, was always confident he would fend off 36-year-old Greene, and was just waiting for an opportunity to come his way.
He said: "I never started to question my own ability. I've practised very hard since I was eight years old and I know that I can rely on my game when it matters.
"I didn't have a great chance until the last frame and when I was asked the question I stepped up and did it.
"I think this is the best prepared I've ever been for the World Championship.
"I've not had the greatest of seasons results-wise but I don't think I've reaped the rewards of the effort I've put in, and I am due."Reuse content