MELBOURNE (AFP) - Fourth-seed Daniil Medvedev navigated a challenging first-round clash against last year's quarter-finalist Frances Tiafoe to kickstart his Australian Open campaign Tuesday.

The 23-year-old, who won four titles last year and was runner-up at the US Open, ultimately showed his class to outlast the American 6-3, 4-6, 6-4, 6-2 on Rod Laver Arena.

It was a tough workout for the in-form Medvedev, who began his year strongly at the ATP Cup, winning four of his five singles matches.

He is gunning for a maiden Grand Slam title.

"It was a really tough first match, it was up and down for both of us. A first round is never easy, especially against someone like Frances," said the Russian.

"There were many moments where I felt I had momentum, but he straightaway came back.

"I think I could do many things better, but it is a big win and I'm happy to be through."

It was always going to be a difficult assignment against Tiafoe, who was looking to repeat his glory run at the Australian Open last year.

Ranked No. 50, Tiafoe was broken twice to slip 4-1 behind in the first set, with Medvedev's power proving too much.

He bounced back with a break and pressed hard for another.

But the Russian - who made the round of 16 last year, losing to eventual champion Novak Djokovic - produced some sizzling passing shots and deft drops to take the set.

They went game-for-game in the second set until Tiafoe broke in a decisive ninth game and levelled at one set all as he lifted to another level.

Another tight set followed. But a loose service game from the American gave Medvedev a 2-1 lead, sealing the set with another impressive drop shot.

The Russian scored a crucial break on Tiafoe's opening serve in the fourth set and the American, who threw his racket to the ground in frustration, was unable to recover.