China's Xiao Guodong reached the second round of the world championship for the first time on Wednesday with a 10-4 win over Ryan Day while world number two Judd Trump crashed to a shock loss.
Xiao, the world number 44, opened up a four-frame advantage on the Welshman and again pulled away to lead 6-3 after Day won three in succession.
Xiao then began the second session in fine form, making two half-centuries on his way to winning the first three frames.
A 98 from Day reduced the arrears slightly before Xiao set up a second-round meeting with world champion Mark Selby.
"It was a bit of an embarrassing day at the office. My concentration was poor all day really," said Day.
Trump, the 2011 runner-up, lost 10-8 to 46-year-old qualifier Rory McLeod.
Trump, who won the opening four frames on Tuesday but trailed 5-4 overnight, continued to struggle on Wednesday and found himself one frame away from defeat at 9-7 when play was halted until the evening.
McLeod, priced at 1,000/1 to win the title at the start of the tournament, then took two frames to finish the job and set up a second-round meeting with Stephen Maguire.
Graeme Dott, the 2006 champion, overcame two-time finalist Ali Carter 10-7.
"I certainly tried to attack the ball as best I could, when it was necessary," said Dott.