(Photo credit: Robert Deutsch-Imagn Images)

Two-time defending champion Jannik Sinner punctuated a big day for Italians at the Australian Open on Tuesday, advancing to the second round when France's Hugo Gaston retired trailing 6-2, 6-1.

The No. 2 seed was firmly in control in Melbourne when Gaston was forced out with an abdominal injury. Sinner fired six aces and 19 winners and saved all three break points in the first two sets.

'I saw that he was not serving with a very high pace, especially in the second set, but it's not a way you want to win the match,' Sinner said. 'He's such a talented player, so I knew I had to play at a very high level, try to be aggressive as possible, which I've done. So I'm very happy, very happy to be back here.'

Up next for the four-time Grand Slam champion is Australian wild card James Duckworth, who outlasted lucky loser Dino Prizmic of Croatia 7-6 (4), 3-6, 1-6, 7-5, 6-3.

Most of Sinner's compatriots also recorded opening-round victories Tuesday. No. 5 Lorenzo Musetti, No. 22 Luciano Darderi and Lorenzo Sonego advanced, though Luca Nardi fell in four sets.

Musetti, coming off a run to the final in Hong Kong, posted a hard-earned decision over Raphael Collignon. The Belgian experienced leg cramps and could not continue in the fourth set when he trailed 4-6, 7-6 (3), 7-5, 3-2.

Musetti's next opponent will be Sonego, who cruised to victory over Spain's Carlos Taberner, 6-4, 6-0, 6-3.

Darderi pulled out a 7-6 (5), 7-5, 7-6 (3) victory over Chile's Cristian Garin, while Nardi fell 7-5, 4-6, 6-4, 6-2 against Chinese qualifier Yibing Wu.

Retiring Frenchman Gael Monfils played in his 20th and final Australian Open, losing 6-7 (3), 7-5, 6-4, 7-5 to Aussie qualifier Dane Sweeny.

'First of all, thank you so much. For me, my journey here with you guys started in 2003, when I came here for the first time,' said Monfils, 39. 'Now we are in 2026 and somehow it is the finish line but thank you so much for this amazing ride. You have been unbelievable, so thank you so much.'

No. 8 seed Ben Shelton won a battle of left-handers, getting past Frenchman Ugo Humbert 6-3, 7-6 (2), 7-6 (5). The American hammered 15 aces and will face Sweeny in the second round. No. 9 Taylor Fritz also won his America vs. France opener, eliminating Valentin Royer 7-6 (5), 5-7, 6-1, 6-3.

No. 15 Karen Khachanov of Russia outlasted American Alex Michelsen 4-6, 6-4, 6-3, 5-7, 6-3. Sixteenth-seeded Czech Jakub Mensik also won a five-setter, edging Spain's Pablo Carreno Busta 7-5, 4-6, 2-6, 7-6 (1), 6-3.

Ethan Quinn, the 2023 NCAA singles champion, upset 23rd-seeded Dutchman Tallon Griekspoor 6-2, 6-3, 6-2. Quinn struck 32 winners and made only 16 unforced errors. Fellow American Eliot Spizzirri also pulled off an upset with a 6-4, 2-6, 6-1, 6-2 defeat of No. 28 Joao Fonseca of Brazil.

Also advancing were No. 31 Stefanos Tsitsipas of Greece, Argentina's Sebastian Baez, American Nishesh Basavareddy, Poland's Hubert Hurkacz, Spain's Rafael Jodar and Czechs Tomas Machac and Vit Kopriva.

--Field Level Media