Third-seeded Alexander Zverev shrugged off a sluggish start to power through his first-round match against rising star Gabriel Diallo as the Australian Open got underway Sunday.

Zverev, the runner-up at Melbourne Park last year, slumped in the first set against the 24-year-old Canadian before rallying on the back of his strong serve to win 6-7 (7), 6-1, 6-4, 6-2 on Rod Laver Arena. He is into the second round at Melbourne Park for the 10th straight year.

"Definitely when I saw the draw, wasn't too happy to be honest," Zverev said in an on-court interview, speaking of the tricky challenge presented by No. 41-ranked Diallo. "He's very young, very talented. Unbelievably aggressive.

"First set wasn't my best tennis, I would say. I was thinking, 'can't get worse than that." It got a lot better after that for me."

No. 1 Carlos Alcaraz, who is bidding to complete the career Grand Slam, saw off Australia's Adam Walton 6-3, 7-6 (2), 6-2.

No. 20 Flavio Cobolli became the first of the seeded men's players to exit the tournament in a 7-6 (7), 6-4, 6-1 loss to British qualifier Arthur Fery.

No. 10 Alexander Bublik advanced over Jenson Brooksby 6-4, 6-4, 6-4, No. 18 seed Francisco Cerundolo beat Zhang Zhizhen 6-3, 7-6 (0), No. 29 Frances Tiafoe overpowered Jason Kubler 7-6 (4), 6-3, 6-2, and Michael Zheng fended off Sebastian Korda 6-4, 6-4, 3-6, 6-7 (0), 6-3 in an all-American first-rounder.

Zheng, a college star at Columbia who advanced through qualifying to make his tour-level debut, will next face No. 32 Corentin Moutet, who was booed after his underarm serve on match point in a 6-4, 7-6 (1), 6-3 win over Tristan Schoolkate.

The Associated Press contributed to this report.