The trio, who have each won their first PDC major title this year, all moved a step closer to a second televised triumph with first round wins at Butlins, Minehead.
Whitlock won the last three legs of his contest against Jamie Caven to progress, finishing the match with a brilliant 111 checkout.
van Gerwen ended reigning champion Kevin Painter’s title defence with a 6-3 success, which included three 180s and a 123 finish from the in form Dutchman.
Thornton was particularly impressive as he swept past Mark Walsh with a 6-1 victory.
The Scotsman faces compatriot Gary Anderson in round two on Saturday afternoon.
Whitlock takes on Ronnie Baxter on Saturday evening, when van Gerwen will face Andy Hamilton for a place in the quarter-finals.
Paul Nicholson was unfortunate to miss out on a last 16 spot as ‘The Asset’ was edged out in a last leg decider by Baxter, while James Wade, Vincent van der Voort, Mark Webster and Raymond van Barneveld also suffered first round defeats.
Mervyn King came out on top in a tight encounter against Terry Jenkins, with ‘The King’ sneaking the last leg to set up a second round clash with van Barnveld’s conqueror Steve Beaton.
Saturday sees the second round action take place over two session before the tournament reaches its conclusion on Sunday.
By Chris Murphy
Image courtesy of Lawrence Lustig/PDC