PARIS, France - Two-time runner-up Simona Halep will again feature in the second week of the French Open.

The World No.1 eased her way past former semifinalist Andrea Petkovic by winning the last eight games to return to the round of 16, 7-5, 6-0.

Halep hit 19 winners and 17 unforced errors over the course of one hour and 28 minutes, as she converted on 6-of-11 break points she created for herself in the match.

Halep's victory advances her to the round of 16 in Paris for the fourth time in the past five years, and keeps her in mathematical contention to keep the World No.1 ranking after this fortnight. 

"I play better and better day by day. I can say that today I really felt the ball, and the game," Halep said after the match. 

"The way that I finished pretty strong gives me confidence. I can say it was the best match here at this tournament."

A grinding opening set which last nearly an hour saw Halep come from an early break down, but the Romanian needed two opportunities to serve out the set before finally putting the German away.

The second set quickly got away from the forner World No.9 after she lost serve in the first game and jarred her right knee on the terre battue, leading to an early medical timeout.

"I saw actually when she hurt herself. I didn't think about that. I just tried to keep the focus there. It's always tough when you cut your rhythm a little bit," Halep said.

"I didn't think about injury. I just kept playing what I did also in first set but a little bit better in the end. I was happy with the performance, and I feel sorry for her that she got injured."

The 2014 and 2017 finalist dropped just one point on her serve in three games in the second set, and won all but six points played overall to advance into a fourth round meeting with No.16 seed Elise Mertens, who dropped just four games in defeating Daria Gavrilova, 6-3, 6-1 in her third round match.