Muguruza, who served for the match in the second set, secured a 6-2 6-7 (5-7) 6-3 over the third-seeded Sabalenka in a battle that lasted almost two-and-a-half hours.

"I just fight and stay there and keep thinking that I'm going to win," Muguruza said.

"If I have an opponent that is playing great, I have to play better."

Muguruza, the highest-ranked unseeded player in the field at No.16, will face Maria Sakkari in the last eight after the Greek Sakkari eased to a 6-2 6-2 win over Madison Keys.

It was the American Keys' second match since returning to the tour after missing the Australian Open with the coronavirus.

Svitolina cruised through her match against Misaki Doi 6-1 6-2.

The Ukraine star was playing for the first time since a fourth-round loss at the Australian Open on February 15, while Doi was on her fifth match in as many days after coming through qualifying.

Svitolina's quarter-final opponent is Victoria Azarenka, who beat Laura Siegemund 6-4 6-2.

Karolina Pliskova, the second seed, was pushed by Ons Jabeur before prevailing 6-4 4-6 7-5 to set up a meeting with Australian Open quarter-finalist Jessica Pegula of the US, who eliminated former French Open champion Jelena Ostapenko 6-2 7-5.

Fourth-seeded Petra Kvitova strolled to a 6-1 6-3 victory over Anastasia Pavlyuchenkova.

The Czech ace will face Estonia's Anett Kontaveit who dispatched three-time grand slam champion Angelique Kerber 6-1 6-4 .

Australian Associated Press