Anastasia Potapova, 18, routs No. 5 Kerber in French Open first round

In her first French Open main-draw match, 81st-ranked 18-year-old Anastasia Potapova ousted No. 5 seed Angelique Kerber in convincing fashion, 6-4, 6-2.

"I was trying to keep some focus on me, on myself, how I'm playing, how I'm running," said Potapova. "Not trying to think a lot about the court, about first round, about Kerber, because of course she's a great player. But, you know, I'm here to play my best. That's what I did."

After trading early breaks before getting back on serve, Kerber blew a 40-0 lead at 5-4 to hand Potapova the opening set. The Russian teen then raced to a 4-0 lead in the second set before eventually taking the match.

Coming into the Sunday contest, Kerber had few clay-court matches under her belt, having withdrawn from the Mutua Madrid Open prior to her second-round match against Petra Martic with a right ankle injury; she then pulled out of the Italian Open to continue to rehab the injury.

"You know, the pain is—I mean, if you play matches, always a little bit different than to the practices," Kerber responded when asked if she felt some pain today. "Of course this is not my excuse and everything. I tried my best. I know that there is still a little bit work to do to really playing matches 100%, to sliding, to jumping on the foot, and on the leg.

"I tried my best, and this is all I can say. I mean, of course I know that there are still few more days or weeks that I have to take care of this."

The three-time Grand Slam champion had a chance to reclaim the world No. 1 ranking at Roland Garros, had she won the title and other results had gone her way. There are now only four women who can leave Roland Garros at No. 1: Naomi Osaka (who could lose in the first round and still remain at No. 1), Karolina Pliskova (needs to reach the final to have a chance), Kiki Bertens (needs to reach the final to have a chance) and Petra Kvitova (needs to win the title to have a chance).

Kerber has now lost in the first round in six of her 12 career appearances at Roland Garros, and in three of the last four years.

Potapova's win over Kerber is the first Top 10 win of her career. The former junior world No. 1 and junior Wimbledon champion will next face either Marketa Vondrousova or Wang Yafan.

"You know, I don't want to think about future," said Potapova when asked about the big picture. "I want to think about every point, every game. And the only thing what I can think about now, it's my next round. It's the second round. And what's gonna happen, nice. If I'm going to win it, great. But I want to keep focused on myself, on my health, and just stay with a clear mind."