Australian Open: Watch Alexander Zverev's 'racket-wrecking' performance while losing to Milos Raonic

Alexander Zverev smashed his racket into the court eight times in frustration after he went 4-1 down in the second set against Milos Raonic.

By that time it was all but over as the big-serving Canadian rolled to a 6-1, 6-1, 7-6 (5) victory on Monday to reach the quarterfinals of the Australian Open for the fourth time.

Raonic dropped the opening game but then rebounded by winning the next eight.

Zverev held serve to end that streak but was broken again two games later and that tipped him over.

The 21-year-old German flopped into his courtside chair and destroyed his racket in eight angry swings. Then he tossed it.

Zverev got the inevitable warning for racket abuse, took a break at the end of the second set and returned from the locker room a much calmer, more composed player.

It was too late as Zverev extended an unwanted streak of never beating a top 20 player at a Grand Slam tournament.

"I played incredible today," said Raonic, the runner-up at Wimbledon in 2016. "I did a lot of things very well. Proud of that."

Zverev only dropped one point on his serve in his first few games until Raonic stepped up the pressure again.

Zverev composed himself to save those two — one with a short slice backhand that Raonic ran for but couldn't retrieve to end a 29-shot rally and another that clipped the baseline.

But Raonic rallied from 3-1 down in the tiebreaker and finally converted on his fourth match point. He'll next play either No. 11 Borna Coric or No. 28 Lucas Pouille in the quarterfinals.

Earlier U.S. Open Naomi Osaka was a set down again and looking for a bit of inspiration.

She thought of how 20-year-old Stefanos Tsitsipas had stunned 20-time major winner Roger Federer and how Frances Tiafoe has advanced to the quarterfinals for the first time. This helped her pull herself together to reach the last eight, too.

No. 4-seeded Osaka had a 4-6, 6-3, 6-4 fourth-round win over No. 13-seeded Anastasija Sevastova to reach the last eight at a major for the second time. She'll next play sixth-seeded Elina Svitolina, who fended off five break points in a game in the third set that went to deuce 11 times, contained 28 points and was pivotal in a momentum-swinging 6-2, 1-6, 6-1 win over 2017 U.S. Open finalist Madison Keys.

"I wasn't really sure what to do at a point. I just try to stick in there," Osaka said. "And also I was watching all these kids winning, like, last night Tsitsipas beat Federer and I was like, 'Woah' — so I decided I wanted to do well, too.

"I think that's everyone's dream," she added.

Another win now and there's potential for Osaka to have a rematch of the U.S. Open final against Serena Williams. The eight-time Australian Open champion Williams was playing top-ranked Simona Halep later Monday in the fourth round. The winner of the Williams-Halep contest will meet seventh-seeded Karolina Pliskova, who beat Garbine Muguruzu 6-3, 6-1 in an hour and is on a nine-match winning streak.

Pliskova, the 2016 U.S. Open finalist, plans to watch on TV: "For sure, it's going to be the match of the tournament so far."

Osaka will be concentrating more now on Svitolina.

Coming off a win at the WTA Finals, Svitolina is aiming to do what Caroline Wozniacki did last year and follow up a title at the season-ending championship with a breakthrough major in Australia.

For a quarter of an hour on Day 8, Svitolina served and served, and served, tossing the ball into the sun, in a desperate bid to hold a game in the third set against Keys.

After that huge hold, she broke the 17th-seeded Keys's serve in at her first opportunity in the next game, and it was all one-way from then on.

"I was happy I could handle the pressure at 1-1 in the third set," Svitolina said. "It was very hard because the sun was just burning my eyes when I was tossing the ball. Very happy I could win that game."

She's taking a 0-3 record in Grand Slam quarterfinals into her next match against Osaka but is taking a different mindset into the match.

Winning in Singapore "gave me a huge boost of confidence, so I don't think about the past anymore," she said. "I only look forward."