Felix Auger-Aliassime recorded one of the biggest wins of his career Saturday, taking down World No. 3 Alexander Zverev to reach the fourth round of the US Open.

The Canadian dropped the first set but found his rhythm and used a barrage of massive forehands to claim a 4-6, 7-6 (7), 6-4, 6-4 victory over the former US Open finalist in a match that took nearly four hours and featured plenty of highlight-reel points inside Louis Armstrong Stadium.

Auger-Aliassime, the No. 25 seed at the year's final major, had never beaten a top-five player at a Grand Slam before Saturday's upset victory.

"This feels good. I've been coming here since 2018. I'm still young, it's been a few years but I'm working my way," the 25-year-old said after the match during his on-court interview.

"The tournament's still going, the job's not done, but this means a lot to me."

Auger-Aliassime's best run at a major came four years ago when he made it to the semifinals at the US Open.

He'll play Andrey Rublev in the next round.

Zverev, meanwhile, failed to reach the second week at Flushing Meadows for the first time since 2018.