Ronnie O'Sullivan suffered his first defeat of 2014 as he was beaten 4-3 by China's Yu Delu in the Players' Championship Grand Final in Preston.
A break of 140 put O'Sullivan within a frame of victory at 3-2 but Yu restricted the world champion to just two points in the final two frames.
"Sometimes a defeat can do you good because I can knuckle down now and get my game into shape," O'Sullivan told World Snooker's website.
"I started slowly here and it cost me."
John Higgins is also through to the quarter-finals after he claimed a 4-2 victory over Ben Woollaston.
The four-time world champion could only register a top break of 56 but saw off Leicester potter Woolaston 4-2 to advance to the last eight for his third consecutive ranking event.
The Scot will next face Marco Fu after the world number eight beat Mark Williams by the same score, registering breaks of 79, 57, 82 and 60.
Mark Allen is also through after he recorded breaks of 113, 54, 75 and 66 to beat Fergal O'Brien 4-1 despite losing the first frame.
Joe Perry was the other winner as breaks of 98, 128, 53 and 61 guided him to a 4-1 win over David Gilbert.
A total of 32 players started the five-day tournament, with £100,000 going to the man who wins Saturday's final.