Exhausted 40-year-old Swiss warhorse Stan Wawrinka battled to an epic five-set win to scrape into the third round on Thursday in his Australian Open farewell.

In Melbourne as a wildcard, Wawrinka pulled heroically through in four hours and 33 minutes against French qualifier Arthur Gea.

Now ranked 139, he won 4-6, 6-3, 3-6, 7-5, 7-6 (10/3) to become the first player aged 40 or over to reach the men's third round at a Slam since Ken Rosewall at the Australian Open in 1978.

The former Australian Open champion is playing his last season before retiring and next faces the American ninth seed Taylor Fritz, who saw off Vit Kopriva of the Czech Republic 6-1, 6-4, 7-6 (4).

"Exhausted. I am trying to last as long as possible on my last Australian Open," Wawrinka said in his on-court interview.

Addressing the crowd, he said: "You gave me so much energy, I am not young anymore so need extra energy from you.

"It is an amazing feeling. It was a long match. I don't know how I am going to recover," he added.

Wawrinka, who made his debut at Melbourne Park in 2006, fell a set down but fought back and rattled off an ace to win the second set.

Gea, who at 21 is nearly half Wawrinka's age, hit back to win the third set and put the veteran on the back foot once again.

Despite his advanced years the three-time Grand Slam champion Wawrinka somehow found some reserves of energy as the sun went down.

He broke to take the fourth set by the scruff of the neck and they went to a deciding fifth.

In front of a frenzied crowd, Wawrinka broke to start the final set and Gea had both knees strapped as an enthralling match went down to the wire.

There was nothing in it as the battling duo slugged it out to a thrilling finale.

It was the 49th five-set match of Wawrinka's career at Grand Slam events, surpassing Roger Federer for the most of any player in the Open Era.

Wawrinka won the first of his majors at Melbourne in 2014, a season during which he peaked at world number three.

Along with that title, he won the French Open a year later and the US Open in 2016.

The triumphs all came at a time when Federer, Rafael Nadal and Novak Djokovic were dominating men's tennis.

In other action, second seed Jannik Sinner of Italy saw off Australia's James Duckworth 6-1, 6-4, 6-2 and next faces American Eliot Spizzirri, who outlasted China's Wu Yibing 6-2, 6-4, 6-7 (4), 4-6, 6-3.

Novak Djokovic systematically dismantled Italian qualifier Francesco Maestrelli 6-3, 6-2, 6-2 in his quest to make more history on Rod Laver Arena.

Lorenzo Musetti, the fifth seed, won the battle of the Italians as he defeated Lorenzo Sonego 6-3, 6-3, 6-4 and will next face Tomas Machac, who beat Stefano Tsitsipas 6-4, 3-6, 7-6 (5), 7-6 (5).

Eighth ‌seeded Ben Shelton had few issues against Australia's Dane Sweeny, ‌claiming a 6-3, 6-2, 6-2 win to set up a meeting with Valentin Vacherot, who defeated Australia's Rinky Hijikata in straight sets.

On the women's side, six-times Grand Slam champion Iga Swiatek blazed past Marie Bouzkova with a 6-2, 6-3 victory as she hunts for her first majors title in Melbourne.

Sixth seed Jessica Pegula had few issues against doubles partner McCartney Kessler, handing out a comprehensive 6-0, 6-2 defeat to her fellow American in 58 minutes and set up a meeting with Russia's Oksana Selekhmeteva.

Fourth seed Amanda Anisimova, also from the United States, booked her place in the next phase with a 6-1, 6-4 win over Katerina Siniakova and the fourth seed will next face compatriot Peyton Stearns.

China's Wang Xinyu made it to the third round of the Australian Open for the first time after a 4-6, 6-4, 6-4 win over the 24th seed Jelena Ostapenko.

Japan's Naomi Osaka saw off Romanian Sorana Cirstea 6-3, 4-6, 6-2. (AFP/Reuters)