China's Lu Ning was edged out by Englishman Tom Ford 6-5 in the fourth round of the UK Snooker Championship here on Wednesday.
Lu, 24, led 1-0, 2-1, 3-2 and 5-4, but he missed a red leading 36-0 in the 10th frame and that proved costly for the 112th-ranked Chinese player.
Ford levelled the score at 5-5 after that and edged home in a match that finished after midnight.
"I should have won 6-4 but I rushed with the red," said Lu. "In the final frame, we both made a lot of mistakes. That's not because we were under too much [pressure], but because both of us were too exhausted physically."
Lu, from northeastern China's Jilin province, started his career in Shanghai's Ding Junhui Snooker Academy and went on to win the Under-21 World Championship. After playing two unsuccessful years in the tour in England, he returned to China before rediscovering his form this season.
"I have achieved my goal in York," he said. "It was a really valuable experience for me," Lu said.
For his part, Ford was relieved to move into the next round. "I could see from the first frame that he was playing really slowly and normally when that happens my head goes and I find it really difficult to stay concentrated. So the thing I am most pleased about with this win, is that I hung in there and managed to get over the line," Ford said.
Earlier, Stephen Maguire upset world champion Mark Williams 6-5, Mark Allen beat Neil Robertson 6-5 and six-time winner Ronnie O'Sullivan crushed Jack Lisowski 6-1.
Williams pulled ahead 4-0 but Maguire created a miracle and will take on either Mark Allen or Neil Robertson in the next round.
O'Sullivan, celebrating his 43rd birthday on Wednesday and bidding for a record seventh title, took just 87 minutes to beat Lisowski. He now meets Martin O'Donnell or Ding Junhui.