Former champion Swiatek knocked out in French Open last 16 by Kostyuk

PARIS, May 31 : Iga Swiatek's 25th birthday celebrations turned sour at the French Open on Sunday as the former champion lost 7-5 6-1 to Ukrainian 15th seed Marta Kostyuk, her bid for a fifth title ending just when she had looked to be rediscovering her rhythm.

There was little to separate the duo in the early exchanges as they twice traded breaks, before Kostyuk came up with a tight hold in the 11th game and raised her level at the end to claim the opening set with a backhand crosscourt winner.

It was the first time that Kostyuk had taken a set off the third-seeded Pole after three straight defeats in their previous meetings, and she sensed a big upset when she went ahead 3-1 in the next set after a battling effort.

The Rouen and Madrid champion held her nerve from there to take her record on clay this season to 15-0, and book a meeting with seventh-seeded Ukrainian Elina Svitolina or 11th-seeded Swiss Belinda Bencic in the next round of Roland Garros.