Marco Fu beat world number one Mark Selby 6-3 to book his place in the quarter-finals of the UK Championship.
Fu took an early 2-0 lead but Selby came back to level before the interval with a 102 break in frame four.
Fu came from behind to win the sixth and seventh frames and although Selby hit back, Fu won frame eight before compiling an 85 break to win the match.
He will face Mark Allen, who put a controversial few days behind him to beat Ali Carter on the other table.
Allen had been the subject of controversy on Tuesday after an outburst at World Snooker chairman Barry Hearn.
But the Northern Irishman put on an impressive display to beat world number eight Carter 6-2.
Allen put together a supreme 101 break in frame three on his way to mounting a 3-1 advantage before the mid-session break.
Carter pulled one back in the following frame but Allen pulled away with breaks of 77 and 67 in frames six and seven.
And he comfortably won the final frame to set up a meeting with world number 30 Fu in the last eight.
In-form Selby was a strong favourite going into the match, but Fu claimed a scrappy opening frame before doubling his advantage with a 52 break in frame two.
But the world number one came back to take the third and he compiled a classy century to level the scores.
And the two-time Masters champion looked in control of the fifth frame until he hit the black off the table on 53 while trying to force it into the bottom pocket.
Fu took advantage of the let-off and put on 64 to take the frame, and he edged frame six to go 4-2 ahead.
Selby replied with runs of 43 and 32 to get back within one but Hong Kong player Fu won the eighth frame on the black before his cool 85 capped the win.