MELBOURNE, Australia (AP) — Defending champion Novak Djokovic challenged a heckler to "say that to my face" during the fourth set of a testy second-round win Wednesday over Alexei Popyrin at the Australian Open.

Before the start of the fifth game of the fourth set, Djokovic walked back behind the baseline and engaged with a spectator, gesturing to him to come down and "say that to my face."

That match had been going for almost three hours by then, and Djokovic had dropped the second set and had to save set points in the third.

After the outburst, he won three straight games to take the match away from the Aussie player en route to a 6-3, 4-6, 7-6 (4) 6-3 victory.

"There was a lot of things that were being told to me on the court," Djokovic explained after the match. "I was tolerating it for most of the match. At one point I had enough, and I asked him whether he wants to come down and tell it to my face... Unfortunately for him, he didn't have the courage to come down... He was apologizing from far away.

"Maybe that was needed for me to be shaken up a bit and start to find the intensity on the court that I needed to have all match," he added with a wry smile.

Advertising

Maybe that was needed for me to be shaken up a bit and start to find the intensity on the court that I needed to have all match. Djokovic on being heckled by a person in the RLA crowd

After clinching the match on a Popyrin error, he turned around to the crowd again and yelled, pumping his fist to celebrate.

Djokovic has been dealing with a sore wrist and said after his opening match — a four-hour, four-set win over 18-year-old qualifier Dino Prizmic — that he hasn't been feeling well.

He credited Popyrin with bringing out a gameplan to unsettle him.

"I haven't been playing my best, but still trying to find form," the 36-year-old Djokovic said. "Particularly in the early rounds, you play players that have nothing to lose. They come out on center court to play their best tennis.

"Hopefully I'll be able to build this as the tournament progresses."

Stefanos Tsitsipas, who lost the final here last year to Djokovic, also had a tough time against an Aussie on an adjacent court in the night session.

Advertising

Tsitsipas had match points in the fourth set and then had to save four set points to force a tiebreaker, which he clinched in a 4-6, 7-6 (6), 6-2, 7-6 (4).

Defending champion Aryna Sabalenka and U.S. Open winner Coco Gauff avoided the early Day 4 upsets in the women's draw to advance to the third round, along with 16-year-old Mirra Andreeva.

Three-time major finalist Ons Jabeur lost 6-0, 6-2 in 54 minutes to Andreeva in Wednesday's opening match on Rod Laver Arena and then 2018 champion Caroline Wozniacki also lost to a young Russian on the No. 3 show court.

Two other 16-year-old players lost their center court matches to highly-ranked players: No. 10 Beatriz Haddad Maia accounted for Alina Korneeva 6-1, 6-2 and Sabalenka overpowered Brenda Fruhvirtova 6-3, 6-2 to open the night session.

Gauff extended her winning streak to nine matches at Grand Slams with a 7-6 (2), 6-2 win over fellow American Caroline Dolehide.

Dolehide served for the opening set at 6-5 before U.S. Open champion Gauff took control in the tiebreaker.

"It was really hard," Gauff said. "If you give her something short, she's going to punish you for it, so if I could go back and do something I'd change that."

Gauff will next play another American, Alycia Parks, who reached the third round of a Grand Slam singles tournament for the first time with a 7-5, 6-4 win over 32nd-ranked Leylah Fernandez.

Jabeur, the runner-up at Wimbledon in each of the past two years, made 24 unforced errors against Andreeva.

"I was really nervous before the match because I'm really inspired by Ons and the way she plays," said Andreeva, who lost in the final of the junior event here last year. "Before I started on the WTA Tour, I always watched her matches and was always so inspired. Now I had the chance to play against her."

It is the second successive year that Jabeur has lost in the second round in Melbourne.

Wozniacki led by a set and a break before losing 1-6, 6-4, 6-1 to 20-year-old Maria Timofeeva, who is making her main draw Grand Slam singles debut.

Wozniacki, who had two children before returning to the WTA Tour last year after 3 1-2 years away, started out on top before Timofeeva turned the match around with some devastating hitting, including 40 winners.

"I'm really a bit speechless now," Timofeeva said. "It was an honor to play here against Caroline. I was going into the match without any expectations. I enjoyed every second of it."

Wozniacki said the match "slid out of my hands . . . it's definitely disappointing,"

Advertising

Jabeur and Wozniacki played their matches under the roof, on Rod Laver Arena and John Cain Arena, respectively, with rain causing the start of matches on the outside courts to be delayed for three hours. It cleared up and the backlog of matches was limited.

Amanda Anisimova continued her comeback from a seven-month mental health break with a 6-2, 6-3 win over Nadia Podoroska. She'll next play Paula Badosa, a 6-2, 6-3 winner over Anastasia Pavlyuchenkova.

On the men's side, fourth-seeded Jannick Sinner had a more routine 6-2, 6-2, 6-2 win over Jesper de Jong on Margaret Court Arena and No. 5 Andrey Rublev beat Christopher Eubanks 6-4, 6-4, 6-4.

Australia's highest-ranked player, No. 10 Alex de Minaur, accounted for Matteo Arnaldi 6-3, 6-0, 6-3. De Minaur will next play Flavio Cobolli, an Italian qualifier who beat Pavel Kotov 7-5, 6-3, 5-7, 6-2.

No. 12-seeded Taylor Fritz progressed along with US Open semifinalist Ben Shelton, the No. 16 seed, who had a 6-4, 6-1, 3-6, 7-6 (5) over local hope Chris O'Connell.

Shelton had match points in the 12th game of the fourth set but couldn't convert, and needed two more in the tiebreaker.

A quarterfinalist on debut here last year, Shelton said he enjoyed the atmosphere that the home crowd gave O'Connell and said he could still hear the chant "Aussie, Aussie, Aussie, Oi, Oi, Oi" in his sleep.