Impressive Osaka makes winning start in Melbourne

World number three Naomi Osaka made light work of France's Alize Cornet on Tuesday in the Japanese star's first competitive match since winning the US Open for a second time.

The three-time Grand Slam champion hit 22 winners to move into the third round of the Gippsland Trophy with a 6-2, 6-2 victory in Melbourne.

"I was really nervous coming here," said Osaka, who won the Australian Open in 2019.

"The last match I played was in New York and I wanted to continue the momentum."

It was an impressive performance from Osaka, who had few problems against Cornet in her first encounter with the French veteran.

Osaka plays Katie Boulter in the next round after the British woman knocked out teenage sensation Coco Gauff 3-6, 7-5, 6-2 in one hour and 43 minutes.

After a tough opening victory over Jil Teichmann, the 16-year-old American started strongly before fading in her second match in consecutive days.

Earlier, defending Australian Open champion Sofia Kenin's long-awaited return to Melbourne Park was brief after her Italian opponent Camila Giorgi retired injured after one set at the Yarra Valley Classic.

The 22-year-old was back at the scene of her stunning breakthrough Grand Slam title last year, where she beat Garbine Muguruza in three sets.

But it was a short stay on Margaret Court Arena with the 76th-ranked Giorgi retiring because of a thigh injury after Kenin clinched a tight first set 7-5.

"I'm happy with the win, the way I played," she said.

"I started off pretty good...just made a little bit too many unforced errors."

The American was upset in the quarter-finals of the season-opening event in Abu Dhabi last month by Greece's Maria Sakkari, ranked 22.

Kenin reeled off three straight games to start the match before going off the boil as Giorgi went 4-3 ahead.

Kenin regrouped before Giorgi called for medical attention at the end of the set and retired.

The Moscow-born Kenin emerged as a serious force in last year's truncated circuit, also reaching the French Open final and rising to a career-high fourth in the world rankings. She plays fellow American Jessica Pegula next.

World number one Ashleigh Barty plays later on Tuesday.