Scott Waites, Gary Anderson, and Raymond van Barneveld have all suffered defeats as the Grand Slam of Darts began in Wolverhampton on Saturday night.
Waites, who beat James Wade 16-12 in last year's final, fell 4-0 behind to Michael van Gerwen before he was eventually defeated 5-3.
Anderson took an early 2-0 lead against Nigel Heydon before he hit back to beat the Scotsman 5-3, while Van Barneveld was ousted 5-4 by Stoke's Ian White, who replaced the injured Simon Whitlock in the tournament.
Last year's runner-up Wade was pushed all the way by Dave Chisnall before he overcame the former Lakeside runner-up 5-4, and Justin Pipe saw off Terry Jenkins 5-1.
Elsewhere, Ted Hankey crashed to a 5-0 loss to Dean Winstanley, Wayne Jones beat Brendan Dolan 5-2, and Mark Walsh overcame Tony O'Shea by the same scoreline.
