BEIJING, China - No. 16 seed and defending champion Caroline Wozniacki soared into her fifth quarterfinal at the China Open with a 7-5, 6-4 victory over Katerina Siniakova of the Czech Republic on Thursday.

Having trailed by a break twice in the opener, the Dane rounded into form late in the set to win it, and did the same in the second despite surrendering an early lead to reach the last eight in the Chinese capital for the fifth time in her career. 

"I was trying to stay aggressive. I was trying to move the ball around a lot. I think I was successful most of the time, but there was a couple of games where she played good or I played a little sloppy," Wozniacki said after the match.

"But all in all, I think I did that pretty well. Then I tried to just stay aggressive on her forehand side, as well.

"I think every match is always different. I just go in and try to do my best. I had a game plan in mind. I just tried to execute that."

Siniakova, who dropped just seven games across her first two matches in Beijing against Chinese wildcard Wang Xiyu and former French Open champion Jelena Ostapenko, showed off some of the same scintillating form early on against the former World No.1.

The World No.47 was the first to break serve in the encounter to lead 2-1, and though she'd lose serve to love in the ensuing game, she bounced back into the lead with a second break of Wozniacki's serve in the seventh game.

As a lengthy opening set, which lasted three-quarters of an hour, wore on, however, the 23-year-old grew more erratic off the ground, particularly on the forehand side, and she surrendered four of the last five games to fall behind by a set.

The defending champion's run of games grew to eight of 10 as she won four of the first five in the second set as well to lead to 4-1, and she held off Siniakova down the stretch to book a spot in her first quarterfinal since reaching the last eight at the Volvo Car Open in April.

After the Czech saved a break point which would've seen her trail 5-1, she played some of her best tennis with her back against the wall to get the set back on serve. 

Siniakova denied Wozniacki three match points on serve in the ninth game, breaking for a fifth time to stay alive, but Wozniacki sealed a ninth straight victory in Beijing with a seventh overall break in one hour and 37 minutes.

Despite winning five of the seven break points she created in the match, Siniakova was unable to overcome 43 unforced errors in the match.

Landing 70 percent of her first serves, the Czech was unable to gain much traction in her service games, winning just 48 percent of the points behind her first serve, and 33 percent of points behind her second. 

Up next, Wozniacki will face Daria Kasatkina, winner of an all-Russian clash against Ekaterina Alexandrova, as she looks to win her 10th straight match in Beijing.

"Kasatkina mixes up the pace very well, tries to slow down the ball, uses the forehand to open up the court and play the angles," Wozniacki said.

"I'm happy to have played well so far in the tournament. I've been feeling pretty good. That's always a plus. We'll just see."

"Hopefully it's not the end of the tournament for me. Hopefully I have a couple more matches in me. I'm just going to go and see."