Williams and Osaka crash out of French Open

While it is a big surprise on paper, Williams arrived in Paris desperately short of matches and with her fitness in doubt because of a left knee problem.

The 37-year-old had not played two full matches in any tournament since the Australian Open in January and Kenin was simply far sharper and quicker around the court.

Williams gave credit to Kenin, saying: "I think she played really well. I feel like she, in that first set in particular, she hit pretty much inches from the line, and I haven't played anyone like that in a long time."

The 23-time grand slam champion admitted she is "pretty far away" from being in top shape but believes she does have enough time to correct that for Wimbledon, where she reached the final last year.

"I hope so," she said. "I'm still working on it and working on getting there. So I think it will be enough time."

Williams added that she would consider taking a wild card into a grass-court warm-up event for the first time since 2011.

Kenin, who next faces eighth seed Ashleigh Barty, struggled to hold back tears as she said: "It's a lot of emotions. Serena's such a great player and a true champion, so all respect to her. Playing against Serena you've really got to fight for every point. I'm just so happy with this win."

Earlier, Osaka's winning grand slam run was ended by Czech Katerina Siniakova.

The world number one had won 16 consecutive slam matches dating back to a third-round loss against Angelique Kerber at Wimbledon last year, taking in titles at the US Open and Australian Open and two victories here.

But she had been living extremely dangerously, and against Czech Siniakova, the world doubles number one and ranked 42 in singles, she could not find a way back, losing 6-4 6-2.

Asked how disappointed she felt, Osaka said ruefully: "It would go from one to 10 and I'm like at a 100 right now.

"Definitely I think this tournament, I have had a feeling that was different to the other grand slams. Usually I find it very freeing and fun, and this time around I was kind of tense the entire time.

"I just feel like there has been a weight on me, and I know that's because everything is sort of new. I have played the French Open before but not in this situation. So it hasn't been the happiest of times."

The pressure had not just come from outside, though, as Osaka said in Australia she was already thinking about winning all four grand slam titles this year.

"It's weird but I think me losing is probably the best thing that could have happened," she added. "I think I was overthinking this calendar slam.

"This is something that I have wanted to do forever but I have to think about it like, if it was that easy, everyone would have done it. I just have to keep training hard and put myself in a position again to do it hopefully."

Siniakova next faces American Madison Keys, who battled to a 6-3 6-7 (5) 6-4 victory over Anna Blinkova.

World number one Simona Halep had dropped sets in both her opening two matches but needed only 55 minutes to breeze past Lesia Tsurenko 6-2 6-1, the Ukrainian failing to hold serve during the match.

Halep's next test will come against Polish debutant Iga Swiatek, who only turned 18 on Friday and continued her superb tournament by beating Olympic champion Monica Puig 0-6 6-3 6-3. Swiatek won the girls' singles title at Wimbledon last summer.

There are three teenagers in the last 16, the youngest of whom is 17-year-old Amanda Anisimova, who beat Irina Camelia Begu 7-6 (6) 6-4.

The American is the youngest woman in the fourth round at Roland Garros since Martina Hingis in 1998.

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