U.S. champ Naomi Osaka into quarterfinals at Australian Open

The US Open champion triumphed 4-6, 6-3, 6-4 to set up a last-eight clash with Ukrainian sixth seed Elina Svitolina and said she was learning how to better deal with recovering from losing a first set.

"To reach the quarter-finals here, of course, I'm very happy", she told reporters.

"I wasn't really sure what to do at a certain point, but I just tried to stick in there", Osaka said.

"I don't know I just walk around and everyone is just like normal".

The pair had split their four previous match-ups.

"I was thinking I've been in this position before - actually it was a little bit worse last time".

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.

Apart from the second set, Keys didn't quite find her range with her ground strokes and 34 unforced errors. She was almost broken back in the ninth game and bounced a ball high into the air in her frustration, but came out the victor of a 23-shot rally and served out the set.

Hsieh was troubling Osaka with her groundstrokes

She held firm when it counted, however, breaking Sevastova in the seventh game of the decider before sealing the match after one hour and 47 minutes with an imperious forehand down the line.

She's taking an 0-3 record in Grand Slam quarterfinals into her next match against Osaka, but is taking a different mindset into the match. Serena Williams' relentless drive towards an eighth Australian Open title cranked up another gear Saturday with a third round drubbing, as Naomi Osaka and Elina Svitolina survived big scares to stay in the hunt.

"I was watching all these kids winning last night - Tsitsipas beat Federer and I was like, 'Whoa.' So I decided that I wanted to do well, too", she said.

Japan's Naomi Osaka has come from a set down to win through to the quarter-finals.

"I think I believe in myself more this year than I have last year".

Osaka has only reached the quarterfinals of a major once before in her career.

Svitolina has never progressed further than the quarter-finals of a grand slam and the result mirrors last year's final eight showing at Melbourne Park, when she lost to Belgian Elise Mertens.

She is looking to become the 10th woman in history to win the U.S. Open and Australian Open back-to-back.

Serena Williams consoles crying opponent after win: 'You did amazing'
But that ends Monday, when Williams faces Simona Halep in the fourth round of the Australian Open . At the beginning of this tournament, few people picked Halep to be a threat deep into the draw.