BEIJING, China - No.4 seed Naomi Osaka extended her Asian swing winning streak to seventh consecutive matches as she dispatched in-form Alison Riske, 6-4, 6-0, to reach the quarterfinals of the China Open.

The Toray Pan Pacific Open champion sealed Thursday's third round victory against the unseeded American in emphatic fashion, winning the last 10 games against the Dongfeng Motor Wuhan Open runner-up to reach the last eight.

"Today I was kind of happy because the first set was really tight. I was thinking that it's been a while since I've kind of had to be really serious," Osaka said after the match.

"It seemed like she was the type that would use my pace, especially on the forehand. I just tried not to give her too much."

Riske, looking for her third win against a Top 10 player in the past two weeks, started the quicker of the two players.

She was the first to break serve between the two, after getting to deuce in Osaka's first two service games and being unable to win either game.

The World No.24 dropped just four points in her first three service games and took a 4-2 lead, but a hold to 30 in the sixth game of the opener proved to be the last game she'd win in the encounter. 

"I'm relaxed, but I'm a little bit angry. Like it's an angry relaxed. I know after Australia I was like, I'm going to have fun. It was not fun. I did not have fun. Then after US Open, I know I said I was kind of 'satisfied' with that," Osaka assessed.

"I took a week break. I was sorting out my thoughts. I was thinking that I have to at least end the year well. Osaka is coming up, and I always play well in Japan, like I have to win that tournament, and I have to do well in the Asian swing."

The two-time Grand Slam champion rounded into form from then on, drawing level at 4-4 with her first break of the match, and then added a second to seal the opening set.

With momentum fully on her side, Osaka sprinted through the second set in under a half hour, and lost just 10 points overall to seal her spot in the quarterfinals in one hour and 13 minutes.

Up next, Osaka faces Bianca Andreescu, in a match of the last two US Open champions, after the Canadian dispatched American qualifier Jennifer Brady later on Thursday.

Read more: Andreescu outguns Brady, books Osaka clash in Beijing: 'It's going to be a lot of fun'

"I was watching her play Toronto when I was there. It's pretty obvious, but she seems to be -- well, she is an amazing player. I feel like she's doing better than I was last year, so it's all cool. I have to learn from her, too," Osaka said of Andreescu.

"I noticed that she seems to be very focused. She plays a lot of three sets. I think someone that plays a lot of three sets, it shows that they don't really care about the -- like they can just keep building off.

"Obviously, she won a Grand Slam. That's one of her very good traits."