Serena Williams’s French Open clay prep ended Tuesday in Parma where the 23-time Slam winner was upset by Czech Katerina Siniakova.

The 39-year-old Williams enjoyed an Italian wildcard in her opener, but today the top-seeded Williams met Siniakova who has been seeded in Grand Slams and won doubles Slams. The first-time meeting went the way of the 25-year-old who won it going away 7-6(4), 6-2.

Siniakova proved the steadier player as Serena sprayed errors and looked slow at times on the court.

“If you go to play against a player like this, you really have nothing to lose, so I came up and wanted to enjoy it,” Siniakova said.

“In the beginning I was so nervous, but when it was 1-1 everything just came down and I was just really enjoying it – I was feeling so free and so easy that it just really went my way. So I should really try harder to feel like this in every match, because you should enjoy what you’re doing, and that’s what I’m trying to find. I can play like this. I can do it not just in one match, and I hope it will not be just this match.”

Serena ends her clay prep 1-2 after losing her opener last week in Rome to Nadia Podorosva.

Serena lost, but Americans had a good day as Coco Gauff, Sloane Stephens and Amanda Anisimova all advanced.