Ash Barty is tough to beat under any circumstances, especially when she’s on the ropes.

She proved that again Monday.

The world’s top-ranked player has reached the Miami Open quarterfinals, getting there by holding off 14th-seeded Victoria Azarenka of Belarus 6-1, 1-6, 6-2. It was Barty’s 17th win in her last 20 three-set matches, two of those victories for the Australian coming so far in this tournament.

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"That’s a cool stat," Barty said.

This, too, was cool: The match lived up to its showdown potential, with the reigning Miami Open champion and current world No. 1 in Barty facing someone who has won the Miami title three times and a previous world No. 1 in Azarenka.

Barty rolled in the first set, Azarenka in the second. But the third — as they tend to be — was all Barty, who was never in trouble in the deciding set even after nearly two hours on the court in midday South Florida heat and humidity.

"It’s just about staying in the fight," Barty said. "It’s about not relenting, not giving up regardless of whether you lose a set or you get a break, whatever it might be. I think it’s just about trying to hang around and I’ve worked my backside off off the court to make sure that I feel like I’m good physical condition to play tennis."

Another three-set win went to fifth-seeded Elina Svitolina of Ukraine, who needed nearly 2 ½ hours to beat ninth-seeded Petra Kvitova of the Czech Republic 2-6, 7-5, 7-5 and earn her ticket to the quarterfinals.

"It was not easy conditions," said Svitolina, who has already matched her best Miami finish by making the quarters. "I was trying to fight, trying to find a way, one extra ball over the net."

Barty will next face No. 7 seed Aryna Sabalenka, a 6-1, 6-2 winner over No. 19 seed Marketa Vondrousova. Svitolina will play either unseeded Anastasija Sevastova or wild-card Ana Konjuh in the quarterfinals.

No. 2 women's seed Naomi Osaka of Japan was playing her round of 16 match later Monday against No. 16 seed Elise Mertens of Belgium. Jessica Pegula of the U.S. was scheduled to play Monday night, the No. 29 seed taking on No. 23-seeded Maria Sakkari of Greece.

Among the men, 26th-seeded Hubert Hurkacz of Poland upset sixth-seeded Denis Shapovalov of Canada 6-3, 7-6 (6). Shapovalov was clearly frustrated with some calls that the Hawk-Eye Live technology — the system that replaces live lines judges with cameras — saw one way and he saw another way.

"We're getting used to that, that Hawk-Eye life," Hurkacz said. "It's a little bit different."

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In other third-round men’s matchups, 12th-seeded Milos Raonic of Canada topped 20th-seeded Ugo Humbert of France 6-4, 7-5, and 2014 U.S. Open champion Marin Cilic of Croatia defeated Italy’s Lorenzo Musetti 6-3, 6-4.

Cilic will meet fourth-seeded Andrey Rublev of Russia next. Rublev rolled past Hungary’s Marton Fucsovics 6-2, 6-1 — beating him head-to-head for the third time in the last 22 days, and that doesn’t even include a walkover victory over Fucsovics in Qatar in that span.