Ding Junhui suffered a stunning upset at the hands of 41-year-old Irishman Leo Fernandez in the first round of the UK Championship in York.
The world number three and twice former winner of the title lost five frames in a row as Fernandez clawed back from 5-1 down for a famous 6-5 win.
Fernandez, the world number 130, had not won a match in four tournaments since returning from a 15-month ban after admitting playing a foul shot to facilitate a betting sting in a World Championship qualifier last year.
But he potted the pink and black to edge a tight decider and stun Ding, who first won the title when he beat Steve Davis at the age of just 18 in 2005.
Marco Fu avoided a similar fate as he beat veteran Nigel Bond 6-2, while Mark King was a quick 6-0 winner over Boonyarit Keattikun of Thailand.