French Open: Angelique Kerber Stunned by Kiki Bertens in Opener

Australian Open champion Angelique Kerber crashed out in the first round of the French Open on Tuesday as the German third seed lost 6-2, 3-6, 6-3 to Kiki Bertens, the world number 58.

Bertens, who won her second career title at Nuremberg on Saturday, broke Kerber twice to claim the opening set on Court Philippe Chatrier.

Kerber responded in the second set to force a decider, but Dutchwoman Bertens completed a shock victory to set up a second-round tie against Italy's Camila Giorgi or French wildcard Alize Lim.

Kerber's preparations for Roland Garros were far from ideal, with the 28-year-old failing to win a match at Madrid or Rome before withdrawing from last week's Nuremberg event with a shoulder injury.

Upset complete. World No. 58 @kikibertens downs AO champ & No. 3 seed Angelique #Kerber 6-2 3-6 6-3. #RG16 pic.twitter.com/ZLQBHDh4ar

- Roland Garros (@rolandgarros) May 24, 2016

The German struggled and committed 28 unforced errors compared to just nine winners, taking a medical timeout when trailing 3-0 in the final set to undergo treatment on her ailing shoulder.

On her run to the title in Melbourne, Kerber had saved a match point in her opening match against Japan's Misaki Doi, but there was no great escape this time.

"I'm disappointed that I lost now here the first round, but that's sport and that always can happen," said Kerber.

"That was for sure not my best tennis I played today. I know that you must play your best tennis in the first rounds, as well, because everybody is a tough opponent to play. I was trying it. It was not my day."

Kerber added her shoulder issues were a recurrence of the injury that forced her out of the warm-up tournament in Nuremberg.

"Yeah, the pain is the same, but I don't know if it's better or good. I mean, I just left the court. I hope it's not so bad, but, yeah, I start feeling it in the second set. It was getting worse and worse, but I hope it's not too bad."