Second-seeded Angelique Kerber celebrated her birthday by dropping just one game against 240th-ranked wild-card entry Kimberly Birrell at the Australian Open.
Kerber, who won Grand Slam titles in Australia and the U.S. Open in 2016 and at Wimbledon last year, beat Birrell 6-1, 6-0 on the day she turned 31.
"I always enjoy my birthday here. I think it's the 12th time in a row," Kerber said. "I'll never forget the birthdays here in Australia."
The crowd sang "Happy Birthday" as she left the court.
Kerber moved into a fourth-round match against American Danielle Collins, who beat No. 19 Caroline Garcia 6-3, 6-2.
CAROLINE GARCIA KNOCKED OUT
Danielle Collins has beaten No. 19-seeded Caroline Garcia 6-3, 6-2 at the Australian Open to reach the fourth round of a major for the first time.
The 25-year-old American, who opened with an upset win over No. 14 Julia Goerges, had never previously won a main-draw match in five previous Grand Slam tournaments.
Against Garcia, she converted four of her five break points and was only broken once.
Her next match is against either No. 2 Angelique Kerber, the 2016 Australian champion, or 240th-ranked Kimberly Birrell, the Australian wild-card entry who ousted No. 29 Donna Vekic in the second round.
STEPHENS SURVIVES TIEBREAKERS TO MOVE INTO ROUND 4
Sloane Stephens survived two tiebreakers to beat No. 31-seeded Petra Martic 7-6 (6), 7-6 (5) and advance to the fourth round at Melbourne Park.
The fifth-seeded Stephens, the 2017 U.S. Open champion, will next play Anastasia Pavlyuchenkova, who beat Aliaksandra Sasnovich 6-0, 6-3.
AMNISIMOVA BEATS SABALENKA IN STRAIGHT SETS
Speechless🙆🏼♀️🙏🏽but let’s keep this dream week going pic.twitter.com/gPxbvbdt42— Amanda Anisimova (@AnisimovaAmanda) January 18, 2019
Amanda Anisimova has beaten 11th-seeded Aryna Sabalenka 6-3, 6-2 to reach the fourth round of the Australian Open.
The 17-year-old American is the youngest player still in contention in the women's draw at Melbourne Park and has dropped just seven games against seeded players in the last two rounds. She broke Sabalenka's serve four times in the 65-minute match and fended off the only break point she faced.
Anisimova, who beat No. 24 Lesia Tsurenko 6-0, 6-2 in the second round, had never won a match in a major. She had first-round exits in her two previous main-draw appearances.
Sabalenka won the title at Shenzhen to start the season and reached the fourth round at last year's U.S. Open.
BARTY THROUGH TO ROUND 4
See you next week 🙈🤗🇦🇺💚💛 pic.twitter.com/KeYTHMe7gL— Ash Barty (@ashbar96) January 18, 2019
Local favorite Ashleigh Barty has become the first player through to the fourth round at Melbourne Park with a 7-5, 6-1 win over Maria Sakkari at Rod Laver Arena.
Barty received treatment for an apparent stomach muscle ailment at the end of the first set but appeared not to be affected for the rest of the 82-minute match.
Barty will play either Maria Sharapova or defending champion Caroline Wozniacki in the next round. They play their third-round match later Friday at Rod Laver Arena, with defending men's champion Roger Federer's match against American Taylor Fritz in between.
Rain forced a continuing delay to the start of matches on outside courts. The roofs on all three main arenas were closed.