Fifth seed Andrey Rublev celebrated like he had won the Australian Open after surviving a dramatic first-round epic against plucky Brazilian Thiago Seyboth Wild.

The Russian seemed to be cruising into the second round after winning the first two sets on Sunday but suddenly found himself in a struggle.

Staring down the brink in the fifth-set match tiebreaker, Rublev then found another gear to take down world No.78 Seyboth Wild 5-7 4-6 6-3 6-4 7-6 (10-6).

After securing the match, the 26-year-old roared in pure relief in a huge show of emotion.

Rublev remains Australian world No.10 Alex de Minaur’s projected fourth-round opponent.

“I will not forget this match, Thiago is a super dangerous player, super talented,” Rublev said.

“When I was losing 4-1 I mentally give up and maybe that’s what helped me in the end, I went with nothing to lose.”

Earlier, Jannik Sinner’s bid for his first grand slam title got off to a convincing start after the Italian eased past Dutch challenger Botic van de Zandschulp.

The fourth seed was broken once by van de Zandschulp during their two hours and 34 minutes on Rod Laver Arena but was never seriously troubled, winning 6-4 7-5 6-3.

After not taking part in any of the pre-Australian Open tournaments, the 22-year-old was able to shake off some rustiness against the world No.59 in his opening-round match.

“It’s my first match of the season. It means a lot to me to start off with a win,” Sinner said.

“Physically I feel good. The first match of the season is never easy, but I think I’m in good shape.”

An exciting prospect for years, Sinner appears ready to take the next step in 2024 after finishing last year as arguably the hottest player on the ATP Tour.

He beat major winners Carlos Alcaraz and Daniil Medvedev on his way to the Beijing title.

Sinner then beat world No.1 and 10-time Australian Open champion Novak Djokovic twice in the space of a week at the ATP Finals and the Davis Cup in November.

He is yet to qualify for a grand slam final, with his best result at the Australian Open a quarter-final in 2022.

Coached by Australian Darren Cahill, the classy right-hander looms as one of the toughest obstacles to Djokovic’s hopes for a record-extending 11th title at Melbourne Park.

Meanwhile, 2018 Australian Open finalist Marin Cilic has bowed out of his first major since 2022 with a 6-1 2-6 6-2 7-5 defeat to Hungary’s Fabian Marozsan.

The Croatian veteran was restricted to just two matches last year after struggling with knee issues.

The one-time major winner’s only match in the lead-up to the Open was a loss to German Jan-Lennard Struff in Hong Kong on January 1.

Marozsan will face Argentinan 22nd seed Francisco Cerundolo in the second round after he survived a five-set thriller against Australian qualifier Dane Sweeny.

Meanwhile, 2022 semi-finalist Matteo Berrettini has withdrawn from the tournament after suffering an injury to his right foot.

The Italian will be replaced in the draw by Zizou Bergs, who will face Greek star Stefanos Tsitsipas in the first round.

-AAP