Shaun Murphy was ousted in the first round of the Northern Ireland Open, losing 4-1 to world number 97 Chen Zifan.
The former world champion, who defeated Ronnie O'Sullivan to win the Champion of Champions tournament in Coventry eight days ago, was thoroughly outplayed in the first three frames - during which he scored 13 points to Chen's 279.
He averted a 4-0 defeat with a break of 68 but there was no way back at Belfast Waterfront Hall.
Neil Robertson endured no such drama against Jamie Jones with a 4-1 win, with Antrim's Mark Allen a 4-2 victor over Sanderson Lam.
Another former world champion, Ken Doherty beat Peter Lines 4-2, while veteran Jimmy White sealed his place in the second round by edging Dominic Dale in a contest that went to the final frame.
Adam Duffy progressed with a 4-2 win over Rory McLeod having made the event despite two missed flights.
Defending champion Mark King is safely into the next round with a 4-1 win over Matthew Bolton, having scored a 50 break in the third frame.