MELBOURNE, Australia (AP) — Daniil Medvedev finally worked out how to a win a five-setter. All by himself.

The fourth-seeded Daniil Medvedev was 0-6 in five-setters, and his match against No. 28-seeded Filip Krajinovic looked like it was going all the way in the third round of the Australian Open.

After some angry outbursts from an increasingly animated and chatty Medvedev directed at his box in an otherwise empty Rod Laver Arena, his coach, Gilles Cervara got up and left.

“He said just before leaving that he’s sure I’m going to win the match. He’s going to leave me alone to be more calm," Medvedev explained in his post-match, on-court TV interview after Saturday's 6-3, 6-3, 4-6, 3-6, 6-0 win. “It was a good thing to do. Luckily I won."

Medvedev had been bothered by a problem with his upper left leg and left the court with a trainer for a medical timeout late in the fourth set.

While he was falling behind in that set, Medvedev yelled after dropping a point: “Unbelievable! This is unbelievable!”

When he fell behind 5-2 in the fourth, Medvedev shouted, “I never saw something like this!”

He returned to better much play in the deciding set, smacking an inside-out forehand winner to a corner to close an 18-stroke exchange and break to go up 2-0.

He didn't drop another game as he seized the momentum back from Krajinovic, who was previously 4-1 in matches that went the full five sets.

“In contrary with previous matches where I could get tight ... here I was really calm to finish the match," Medvedev said. “Really happy I got the five-set win."

The win stretched Medvedev’s winning streak to 17 matches, including his successful run to the title at the 2020 season-ending ATP Finals.

Medvedev, the U.S. Open finalist last year, will next play Mackenzie McDonald, the unseeded American who beat Lloyd Harris in straight sets to equal his best Grand Slam result by reaching the round of 16 at the Australian Open.

The No. 61-ranked Jessica Pegula reached the fourth round by drubbing Kristina Mladenovic 6-2, 6-1.

Even Pegula seemed surprised by her best career showing at a major tournament, which started with a first-round win over two-time Australian champion Victoria Azarenka.

“I don’t really expect to be playing this good next match,” Pegula, the daughter of Terry and Kim Pegula, owners of the NFL Bills and NHL Sabres, said of her fourth-rounder against No. 5-seeded Elina Svitolina.

Svitolina, a tour veteran from Ukraine who has won 66 Grand Slam matches, needs one more win to match her best showing at Melbourne Park. She was a semifinalist at both Wimbledon and the U.S. Open in 2019.

There were no fans in the stands due to the start of a five-day lockdown imposed by the Victoria state government in response to a COVID-19 outbreak at a quarantine hotel. Up to 30,000 spectators daily — 50% of capacity — had been admitted on previous days.

No. 25-seeded Karolina Muchova staged an astounding second-set comeback from a 5-0 deficit in near silence, which only made the turnaround seem more bizarre as she beat No. 6 Karolina Pliskova 7-5, 7-5.

Muchova played in an empty Rod Laver Arena.

“It’s a big difference,” she said. “I was actually getting, like, happy yesterday morning that I’m finally going to play on a bigger court and there’s going to be a crowd. But unlucky now for five days here. Hopefully then it’s going to be back again.”

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