Mark Selby lost to Liang Wenbo in the last 32 of the Wuxi Classic, his first defeat since becoming world champion.
Selby, who beat Ronnie O'Sullivan seven weeks ago at the Crucible, went down 5-3 to China's world number 26 in the new season's first ranking event.
Leicester's world number one levelled the game from 2-0 down but failed to pot a ball in the final frame as Wenbo set up a last-16 match with Joe Perry.
Defending champion Neil Robertson won 5-3 against Michael Georgiou in China.
Alan McManus beat four-time world champion John Higgins in the all-Scottish encounter, recovering from 3-1 down to win 5-4.
Finland's Robin Hull hit two century breaks in a 5-3 success over Graeme Dott.