MELBOURNE, Australia — Second-seeded Caroline Wozniacki is through to the Australian Open quarterfinals and with a chance to regain the No. 1 ranking in women’s tennis.
Wozniacki beat Magdalena Rybarikova, 6-3, 6-0, on Rod Laver Arena Sunday. Rybarikova double-faulted on break point to open the second set and start Wozniacki on her way to a dominant victory in 63 minutes.
Since nearly being eliminated in the second round by Jana Fett — Wozniacki trailed, 5-1, in the third set before winning the last six games — she has won her next two matches in straight sets.
Wozniacki plays Carla Suarez Navarro in the quarterfinals. Suarez-Navarro defeated Anett Kontaveit, 4-6, 6-4, 8-6, in the fourth round.
Angelique Kerber, the 2016 champion, routed Maria Sharapova, 6-1, 6-3, in a third-round win Saturday that showcased her credentials as a title contender and ensured she’ll be the only Grand Slam champion still playing in the second week in the women’s draw.
Roger Federer and Novak Djokovic were almost as ruthless in their straight-sets wins Saturday night. It was Federer’s 90th match win at Melbourne Park.
Women’s No. 1 seed Simona Halep took a longer route — equaling a mark in Melbourne for endurance but signaling, perhaps, that she’s closer to a Grand Slam breakthrough.
It took Halep 3 hours and 45 minutes to beat American Lauren Davis, 4-6, 6-4, 15-13.
The third set took 2 hours, 22 minutes. Halep wasted chances to serve for the match in the ninth, 11th, and 15th games, then had to save three match points in the 22nd. There were 11 service breaks and two medical timeouts — for Davis to get treatment on both feet — before Halep converted on her first match point.
‘‘I never played the third set so long, so I’m really happy I could stay and win it. I’m almost dead,’’ Halep said of the match which equaled Chanda Rubin’s win over Arantxa Shanchez Vicario in 1996 — also 48 games — for the Australian Open record in terms of most games.
‘‘I just feel that my muscles are gone,’’ said Halep, who badly twisted her left ankle in the first round. ‘‘My ankle is, I don’t know how it is because I don’t feel it anymore!’’
Halep will next play Naomi Osaka, who beat 18th-seeded Ash Barty, 6-4, 6-2. No. 20 Barbora Strycova beat US qualifier Bernarda Pera, 6-2, 6-2, leaving US Open finalist Madison Keys as the only American woman to reach the fourth round.
Keys advanced, 6-3, 6-4, over Ana Bogdan and will next play No. 8 Caroline Garcia. Sixth-seeded Karolina Pliskova beat No. 29 Lucie Safarova, 7-6 (8-6), 7-5.
Kerber’s next match is against Hsieh Su-wei, who followed up her win over Wimbledon champion Garbine Muguruza with a 6-2, 7-5 win against No. 26 Agnieszka Radwanska to return to the fourth round at Melbourne Park for the first time in a decade.
Sharapova was back at the Australian Open for the first time since 2016, when a failed doping test led to a 15-month ban from tennis.
After two comfortable wins the five-time major winner was growing in confidence, but she had no answers for Kerber, who is on a 12-match winning streak in a kind of comeback of her own after sliding down the rankings last year.
‘‘Of course is quite a big match. I mean, Maria is a champion. She’s always dangerous, especially at the Grand Slams,’’ Kerber said. ‘‘I was really trying to not think about everything around, about against who I’m playing.
‘‘I learned a lot from the last 12, 24 months. I had a great 2016 and last year was a little tougher.’’ Kerber’s year-end ranking dropped from No. 1 in 2016 to 21 last year, when she failed to defend her Australian or US Open titles. ‘‘Anybody who knows me knows I never give up.’’
Sharapova said Kerber was the more aggressive on court and took more risks.
‘‘A lot of things I need to get better at and improve on,’’ she said. ‘‘Today was not enough [but] . . . looking at the overall picture, there’s a lot to build from.’’