Fourth seed Caroline Garcia survived her first big test of the tournament, recovering from a poor first set to defeat Laura Siegemund 1-6 6-3 6-3, and next faces Pole Magda Linette.
Garcia, who won the WTA Finals last season, overcame a shaky start to beat Germany’s Siegemund and reach the fourth round.
Linette upset 19th seed Ekaterina Alexandrova 6-3 6-4 in the late match on Rod Laver Arena.
Aryna Sabalenka prevented her former doubles partner Elise Mertens from reaching the last 16 for a fourth consecutive year with a dominant 6-2 6-3 win over the Belgian.
Sabalenka, who won the Adelaide International 1 earlier this month and has not dropped a set in 2023, next faces Belinda Bencic.
The Belarusian is normally one of the most demonstrative players on court but has made a vow to be more boring to keep herself focused and calm.
“I think like there were a few moments when I was about to throw my racket or scream something, and because I held myself really strong in those moments, I feel like it’s a little bit more natural right now,” she said.
Swiss 12th seed Bencic reached the last 16 here for the first time in seven years after a 6-2 7-5 win over Camila Giorgi.
Italian Giorgi broke Bencic to level the second set at 5-5 before the Olympic champion broke back and served out the match.
Bencic went into the season buoyed by leading Switzerland to the Billie Jean King Cup title in Glasgow in November.
“I’m happy I got a second chance to serve it out but overall I think it was a great match,” Bencic said.
The 25-year-old will hope to use the inside knowledge of her coach Dmitry Tursunov, who helped Sabalenka break through into the top 10.
Tursunov took up the position with Bencic late last season after opting not to continue a trial period with Emma Raducanu.
Former world No 1 Karolina Pliskova brushed aside Russia’s Varvara Gracheva 6-4 6-2 to advance through to a meeting with 23rd seed Zhang Shuai.
“It’s the third round of a slam so there’s never an easy match, no matter who is the opponent, no matter the ranking,” said 30th seed Pliskova.
Czech teenager Linda Fruhvirtova marched through with a battling 7-5 2-6 6-3 victory over compatriot Marketa Vondrousova.
At 17 years and 273 days, world No 82 Fruhvirtova is the youngest woman remaining in the draw.
Her 15-year-old sister Brenda, who qualified for the main draw here, is also among a crop of young Czech women who are expected to make a big impression over the next decade along with 18-year-old Linda Noskova and 16-year-old Sara Bejlek.
History in the making in Melbourne?
The last time two women aged 18 or younger reached the Australian Open quarter-finals was 1999, when Venus Williams made the quarter-finals and Martina Hingis won the tournament
Coco Gauff, 18, and Linda Fruhvirtova, 17, are bidding to match that mark in the second week
Fruhvirtova, who won her first WTA title in Chennai in September, held her nerve in the third set to set up a meeting with Croatian Donna Vekic.
She is the third woman aged 17 or younger to reach the last 16 here since 2010 after American duo Coco Gauff and Amanda Anisimova.
“It feels pretty surreal,” said the teenager. “It’s an incredible feeling. I’m just so happy and excited to be able to say, ‘Hi second week’. I feel good and I’m excited to playing the next match here.”