Ronnie O'Sullivan suffered a first-round defeat at the Shanghai Masters, losing 5-3 to Alan McManus.
World number four O'Sullivan, who was playing his first ranking match of the season, made a 139 break in the third frame and the match was tied at 3-3.
But McManus, who last beat O'Sullivan at the 2003 Scottish Open, won the last two frames for victory.
The pair were meeting for the first time in 10 years, having last played in the 2004 Masters.
O'Sullivan, who won the event in 2009, was making his first appearance in the tournament since 2011, when he lost 5-3 in the last-16 to Anthony Hamilton.
McManus will face either Stephen Maguire or Jimmy Robertson in the second round.
The other first-round match on Monday saw world number seven Shaun Murphy edge past Joe Swail in a final frame shootout.
Despite breaks of 80, 102, 65 and 56, Murphy was taken the distance by the Northern Irishman but a run of 75 helped the English player edge to a 5-4 win.