MELBOURNE, Australia — Jannik Sinner pulled off a remarkable comeback from two sets down to defeat Daniil Medvedev 3-6, 3-6, 6-4, 6-4, 6-3 in the Australian Open men’s final Sunday.

The fourth-seeded Sinner, who had lost only one set coming into the deciding match, appeared destined to lose in straight sets as the third-seeded Medvedev blasted his way to a quick two-set advantage. But the Italian found his feet midway through the final and prevailed in a battle of will and endurance over 3 hours, 44 minutes.

It marks the first career major title for Sinner and an unwanted record for Medvedev, who became the first person in Grand Slam history to lose multiple finals after winning the first two sets. Medvedev also squandered a two-set advantage to Rafael Nadal in Melbourne in 2022.

“I was in a little bit of trouble today at two sets to one down in a little over an hour,” Sinner said. “So I just tried to stay positive, trying to stick to the game plan, which I had to adjust a little bit. Daniil is an incredible player and showed also again he is an incredible fighter.”

Playing in his first Slam final, the 22-year-old Sinner started nervously. Medvedev broke in the third game of the match, no mean feat given Sinner had held serve for 86 of 88 service games coming into Sunday.

The Russian played with pace and aggression early — dictating terms to Sinner and hitting 14 winners to the Italian’s five in an opening set that flew by in 36 minutes.

The nerves didn’t seem to dissipate for Sinner, who struggled to hold his opening service game of the second set, saving four break point chances to level at 1-1. Medvedev held to love before putting Sinner again on the back foot, breaking for a 3-1 lead on the way to taking the second set after the pair exchanged a break each later in the stanza.

Sinner was wayward, sending balls long or missing wide, which was in total contrast to the six matches prior to the final in which he gave up just the one set — in the semifinal to Novak Djokovic.

But all Sinner had to do was extend the match. Entering Sunday, Medvedev had spent 20 hours, 33 minutes on court, the second most of any man entering a major final — and it started to show.

After leaping out of the blocks — serving well and attacking with intent — Medvedev slowed midway through the third set. His first-serve percentage dipped from 86% in the first set to 50% by the third, and he netted 15 unforced errors as Sinner eventually broke in the 10th game of the set, winning it 6-4.

The fourth set was a similar story, as Sinner’s level rose while Medvedev’s wavered. Extended rallies were a friend for Medvedev throughout this tournament, but they were beginning to work against him as fatigue continued to eat away at his game. And Sinner continued to eat away at Medvedev’s lead, again breaking in the 10th game to force a deciding set to rapturous applause in Rod Laver Arena.

Medvedev had a golden chance in the fourth set, but he squandered a break-point opportunity in the seventh game. He wouldn’t get another sniff on Sinner’s serve, as the Italian took control in the fourth and early in the fifth, setting himself up to clinch the decider 6-3 and secure his first Grand Slam title.

Sinner is just the second Italian man to win a Grand Slam; Adriano Panatta won the French Open in 1976. Francesca Schiavone and Flavia Pennetta are Italy’s other Grand Slam champions, having won the women’s 2010 French Open and 2015 US Open, respectively.

Sinner said feeling pressure in the moments he was down two sets was a challenge, and he was “extremely happy” with how he handled adversity on the big stage.

“He played really, really well for the first two sets or 2½ sets. I tried just to play even level, trying to take a couple of chances in the third set, which I’ve done,” he said. “When you win one very important game, the match can change occasionally, and that was the case today.

“I just tried to stay as long in the court as possible, knowing that he has spent so many hours on the court. The more the match goes on, maybe physically I’m a little bit better today, because he played so many hours. I think that today that was the key.”

The Australian Open remains a bittersweet tournament for Medvedev, who has made three finals in Melbourne — his most of any Slam — but has lost all three times.

He said fatigue had taken its toll after a marathon tournament in which he played 31 sets, the most of any player at a major, and described this year’s Australian Open as “by far” the most taxing tournament he has ever played.

“I got a little tired physically, but [in] every other match before, my opponents didn’t manage to take advantage of it,” Medvedev said. “During the match, every time it was the same story, after two sets, my energy level dropped, was dropping because I didn’t have a perfect sleep, I was playing long before.

“So let’s call it my fault because I needed to win easier matches, but sometimes it’s tough.”

History was up against Medvedev, given no man has ever won his quarterfinal, semifinal and final of a major all in five sets.

With the final going the distance, it sets a record for the most five-set matches played at an Australian Open and ties the record for most in a major with the 1983 US Open.

Following his breakthrough win, Sinner will retain his world No. 4 ranking, while Medvedev will hold the No. 3 slot, with a gap opening between the current top four and fifth-ranked Andrey Rublev.