Defending champion Naomi Osaka overcame a second-set blip to beat American Madison Brengle 6-0 6-4 and reach the third round of the Australian Open, staying on course for a potential fourth-round clash with world number one Ashleigh Barty.

The Japanese 24-year-old, who also won the Melbourne Park title in 2019, will next meet 60th-ranked American Amanda Anisimova,

Brengle won just nine points in the first set as an aggressive Osaka served superbly, facing no break points, and returned strong to breeze through the set in just 20 minutes.

The 54th-ranked Brengle, 31, had a big smile as the Rod Laver Arena crowd cheered her first service game win at the start of the second set as Osaka's game dipped.

But the two-time US Open winner soon regained control and sealed the win after 65 minutes on her first match point with a second break of serve in the set.

Ashleigh Barty has dropped just three games in her opening two matches

Ashleigh Barty eased into round three with the minimum of fuss, overwhelming Italian qualifier Lucia Bronzetti 6-1 6-1.

Barty hammered 11 winners to wrap up the first set in 25 minutes and was equally dominant in the second, sealing the victory in well under an hour.

Bronzetti, the world number 142, failed to muster up a single break point over the contest as Barty lobbed, sliced and pounded her into submission in the bright Melbourne sunshine.

Barty is hoping to end Australia's 44-year wait for a homegrown women's champion and was particularly delighted at the turnout for her match so early in the day.

"It was incredible," the 25-year-old said. "It was an awesome surprise to go out there and hear so many Aussies. It was an incredible atmosphere. It was just a lot of fun out there today."

The top seed next faces another Italian in Camila Giorgi.

Twice former Australian Open champion Victoria Azarenka also advanced.

Azarenka, the 2012 and 2013 champion, sealed a 6-1 6-2 victory over Swiss Jil Teichmann with a backhand winner.

Paula Badosa

In-form Paula Badosa strode into the third round for the first time with a dominant 6-0 6-3 win over Martina Trevisan.

The world number six is firming as a contender for a maiden grand slam title after winning the Sydney Tennis Classic last week and easing through her first two matches at Melbourne Park for the loss of only seven games.

It is a stark contrast with last year when, ranked 70th in the world, she spent 21 days in Melbourne quarantine after contracting Covid and crashed out in the first round to a qualifier.

"I'm really proud of myself," the 24-year-old said. "After all, one year ago I was locked in a room.

"So being here and playing centre court, because of me, not because I'm playing a seeded player, because now I'm the seeded player - I'm really happy and proud of myself. It was really special for me to play there."

Next up is Ukrainian teenager Marta Kostyuk, who she beat in the final round of qualifying at Melbourne Park in their only previous meeting in 2019.

Harmony Tan winces in pain

France's Harmony Tan had to be assisted off court in a wheelchair at the Australian Open on Wednesday after suffering calf problems during her second round match against Elina Svitolina.

In her debut tournament at Melbourne Park, world number 107 Tan trailed 6-3 5-7 5-1 before she retired hurt from the early match at Margaret Court Arena.

"It was a rollercoaster match," 15th seed Svitolina told reporters.

"Of course, it's very sad to see her leaving the court in a wheelchair. It's never, never good to see a player getting injured."

Ukrainian Svitolina moved into a third round clash against Victoria Azarenka.

Madison Keys stormed into the next round with a 6-2 7-5 win over Jaqueline Cristian.

The American ran away with the opening set in 31 minutes and broke unseeded Romanian Cristian for a 6-5 lead in the next to seal the win that set up a clash with Wang Qiang after the Chinese player beat Alison Van Uytvanck 2-6 7-6 (7-5) 6-3.

French Open champion Barbora Krejcikova continued her charge at Melbourne Park with a routine 6-2 6-3 win over China's Wang Xiyu. Up next for the Czech is Latvian 26th seed Jelena Ostapenko.

Fifth seed Maria Sakkari made light work of China's Zheng Qinwen, romping to a 6-1 6-4 win to set up a meeting with Veronika Kudermetova in the third round.