The ATP Montreal Masters lost its top two seeds in the space of a few hours on Wednesday as Germany's Alexander Zverev and Canadian Felix Auger-Alliassime both exited the field.

Top seed and world number three Zverev, this year's French Open champion and Wimbledon runner-up, was toppled by Dutchman Tallon Griekspoor, who rallied for a 6-7 (3/7), 6-2, 6-4 second-round upset.

Montreal native Auger-Aliassime had to withdraw before his scheduled night match after injuring his back during training on Monday.

Tournament officials already were fuming at an event in which world number one Jannik Sinner and Novak Djokovic were both high-profile absentees even before the start.

"I'm not going to lie, we were hoping that Felix was going to win at least a few matches here in Montreal," tournament director Valerie Tetreault said.

"He's definitely the player everybody was talking about and people wanted to know when he was going to play."

Zverev was competing for the first time since his Wimbledon final loss to Sinner and began to fade in the second set against world number 69 Griekspoor.

The Dutch winner came within a point of a 5-2 lead in the third set, but found himself square at 4-all as he lost serve.

But the underdog broke the seed straight back and served out the match in one of his biggest victories a game later.

"This is one of the most special wins I've ever had," he said. "I've had a tough season. I was close to throwing in the towel a few times. But I've been working harder in practice and reaching a good level.

"I felt it was about time for a big win."

Fifth-seeded defending champion Ben Shelton rallied from 4-1 down in his second set to overhaul US compatriot Jenson Brooksby 6-3, 7-5, winning six of the last seven games for his 28th victory of the season. (AFP)



Edited by Cecil Wong