World champion Mark Selby suffered a last-16 exit at the German Masters in Berlin, losing 5-2 to a resurgent Anthony Hamilton.
The 45-year-old Hamilton, nicknamed the Sheriff of Pottingham, almost dropped off the professional tour last season.
But he has won 21 matches this season, climbing to 66th in the world, and breaks of 62, 53, 68 and 58 took out world number one Selby.
Hamilton's third quarter-final of the campaign will be against Barry Hawkins, the world number 12 having beaten Ben Woollaston 5-2.
Rising Chinese star Yan Bingtao reached the quarter-finals of a ranking event for the first time with a 5-1 victory over Michael Holt.
Breaks of 56, 115 and 61 helped teenager Bingtao add another fine result to a tremendous rookie season.
The 16-year-old now meets world number two Stuart Bingham, the only player ranked among the top 10 who has made the last eight.
Bingham edged out David Gilbert 5-4 with the Basildon player taking the last three frame to secure victory.
