Zverev ran out 6-3 6-4 to rack up his fifth title of the year after Federer showed signs of physical problems towards the conclusion of Sunday's final.

It was just Federer's third defeat in 38 matches in 2017 but his quest to regain the world No 1 ranking could still arrive next week in Cincinnati if results favour him. He confirmed post-match that he would travel to Cincinnati, but would discover the extent of his injury before deciding whether to participate.

Andy Murray, the current world No 1, will be missing in Cincinnati and will be replaced at the top of the rankings but either Federer or Rafael Nadal later this month.

For Zverev, the 20-year-old German, claiming the Montreal Masters represented a second Masters 1000 win after also lifting the Rome title.