Montreal (Canada) (AFP) - French Open champion Alexander Zverev suffered a 6-7 (³⁄₇), 6-2, 6-4 defeat to Tallon Griekspoor on Wednesday in his opener at the ATP Montreal Masters.

The top-seeded German, who finished runner-up to Jannik Sinner last month at Wimbledon, lost his first match since that defeat shortly after second seed Felix Auger-Aliassime was forced to withdraw before his opener with a back injury suffered during Monday training at his home event.

Dutchman Griekspoor, ranked 69th in the world, dispatched third-ranked Zverev, who had a first-round bye, after two hours and 34 minutes to reach the third round.

He will next face the winner of a later match between Italian 30th seed Matteo Arnaldi and Hungary’s Fabian Marozsan.

Zverev made semi-final runs at the Australian Open, Indian Wells, Miami, Monte Carlo and Munich and lost to Sinner in the Madrid final before capturing his first Grand Slam singles title at Roland Garros.