Ding Junhui has suffered a surprise fourth-round defeat to Ricky Walden at the UK Championship in York.
The Chinese was bidding to become the first player since Stephen Hendry in 1990 to win four consecutive ranking events.
Ding fought back from 1-3 down to level the match at 3-3, but Walden eventually sealed the victory 6-4.
Walden will meet either Judd Trump or Mark Allen for a place in the last four of the tournament.