Defending Australian Open champion Naomi Osaka has shown signs of her best form in a 6-0, 6-4 defeat of American Madison Brengle on Rod Laver Arena.
Osaka was virtually untouchable in the first set, which she won in just 20 minutes, and while she endured some shaky moments in the second, her victory always seemed assured.
The four-time major champion will play another American, Amanda Anisimova, in the last 32, with the victor moving through to a possible match-up with world number one Ash Barty in the fourth round.
Barty faces Italian 30th seed Camila Giorgi in the third round on Friday.
Osaka said she was satisfied with the quality of her returns against Brengle.
"I want to say I returned pretty well," the Japanese 13th seed said in her courtside interview.
"That's not my usual step but I have been really working on it during the off-season, so I'm really glad it came in handy today."
Osaka hit the ground running in the first set. She controlled the game brilliantly from the baseline, using the strength of her groundstrokes to dictate terms to Brengle.
The former world number one also chose the right moments to approach the net, leaving her opponent with few options to play herself into the match.
After being restricted to just nine points in the first set, Brengle found her range in the second.
She finally got on the board when she won her first game to level at 1-1, celebrating the moment by raising her arms in jubilation as the Rod Laver Arena crowd warmly applauded.
Brengle had a series of break points during Osaka's next two service games, but each time the two-time Australian Open winner found a way to hold serve.
But the 54th-ranked Brengle was rewarded for her persistence in the seventh game when she broke Osaka to lead 4-3.
Osaka did not lose her composure, however, and she immediately broke back to level at 4-4.
She did not lose a point in claiming the next two games to seal the result, with the match lasting one hour and five minutes.
Earlier on Wednesday, Anisimova kept her tournament alive with a 6-2, 7-5 victory over Olympic gold medallist Belinda Bencic.
Anisimova won a WTA Tour lead-up event at Melbourne Park earlier this month.
Osaka said she needed to be wary of Anisimova's strengths.
"I know she (Anisimova) has a really good return and a great backhand and I'm expecting it to be a little bit different from the match today," she said.
I think we're both going to take our chances, so it is going to be really exciting."
In other results in the women's draw on Wednesday, French Open champion Barbora Krejčíková defeated China's Wang Xiyu 6-2, 6-3.
The fourth-seeded Czech meets 26th seed Jelena Ostapenko in the third round after the Latvian beat Alison Riske of the US 4-6, 6-2, 6-4.
