Mark Selby came from 9-7 down to beat Mark Williams 10-9 in an epic Bank of Communication Shanghai Masters final.
Williams, usually calm under pressure, squandered chances to win in the closing stages and uncharacteristically lost his cool in the deciding frame.
Leicester's Selby took advantage to win only his second ranking title, improving a record of just one win - the 2008 Welsh Open - from five previous ranking finals. The 28-year-old is in the best form of his life having won 12 consecutive matches, including victory in the Paul Hunter Classic two weeks ago, and is now ranked No 1 in the world for the first time.
Welshman Williams, who was bidding to win his 19th ranking title and seventh in Asia, looked set for victory when he came from 7-5 down to lead 9-7. But he was upset by a decision by referee Eirian Williams in frame 17, when Williams felt that Selby had hit the pink when escaping from a snooker, but after studying a video replay, it was decided that he had hit the red first.
Selby came back to win that frame then took the next after two-times World Champion Williams missed a dead easy green when just a few pots from victory.
In the deciding frame of a marathon contest which finished close to 1am, Selby led 32-0 then laid a snooker behind the brown, and a frustrated Williams swiped wildly at the reds, going in-off and gifting Selby the chance to add enough points to cross the winning line.
"It's a big relief to win my second ranking title because I'd lost a few finals," said Selby, who has also won the Masters twice and took the Wuxi Classic title close to Shanghai earlier this season. "Every time I got to a final I came up against someone playing well. Tonight I wasn't at my best but the luck went my way.
"I played well in the first session and should have been 6-3 up. Tonight I struggled and made so many mistakes, but towards the end I got myself together again and Mark missed a few.
"It's a great feeling to be World No 1, all I wanted to do was to get to the top of the sport. But I have to keep up the hard work because others will want to get ahead of me."
As for the incident in frame 17, Selby said: "It was very difficult for the referee to see which ball I hit first. Mark felt I hit the pink and I wasn't sure. The referee studied it and felt it had hit the red first, and we accepted that."
Williams has now lost in the first two ranking finals of the season having suffered a 9-8 reverse from 8-5 ahead against Stuart Bingham at the Australian Goldfields Open. He said: "Overall Mark played a bit better than me so he deserved it."
In the first session Selby knocked in breaks of 74, 113, 78 and 95 to establish a 5-4 lead over Williams, who made 68, 132, 51 and 67.
Selby pulled away to 7-5 in the evening before Williams took four consecutive frames with a top run of 88. But 36-year-old Williams could not finish the job and had to settle for the £32,000 runner-up prize.
Selby is now heading across the globe for the Brazil Masters, which starts on Thursday.
Bank of Communication Shanghai Masters
Final result
Mark Selby 10-9 Mark Williams.
