Judd Trump and Ronnie O'Sullivan both crashed out of the Coral World Grand Prix in Cheltenham on Thursday.
Trump lost a final-frame decider to fall 4-3 to Kyren Wilson in their last-16 clash in the afternoon session.
Then O'Sullivan was beaten 5-3 by Graeme Dott, who finished with a break of 91 to book his place in the semi-finals.
Trump, the world number one and defending champion, missed the decisive blue in a 37-minute deciding frame as Wilson showed signs of a return to form.
Wilson said: "My game has been there this season but it has been frustrating for me not to get the results. I know I'm capable of producing good snooker on the big stage."
Wilson will play John Higgins in the quarter-finals after the veteran Scot beat China's Zhao Xintong 4-1.
Dott held off a minor fightback from O'Sullivan to claim his first win over his fellow former world champion in nine years.
Playing in his first tournament of the year, O'Sullivan clawed back a 3-1 deficit to level at 3-3, but Dott finished strongly to get over the line.
In the last four Dott will face Tom Ford, who kept his quest for a first tour title alive with a 5-2 win over Gary Wilson.
Neil Robertson fired three centuries to whitewash Mark Williams 4-0 and set up a last-16 clash with Joe Perry, who beat Scott Donaldson 4-2.
