Wimbledon champion Angelique Kerber's French Open challenge lasted little over an hour as she was sent packing by Russian teenager Anastasia Potapova in the first round.
The fifth seed had been a doubt for the tournament with an ankle injury suffered at the start of May and she looked short of matches in a 6-4 6-2 defeat.
Kerber has never been particularly at home on clay but, having added Wimbledon to her 2016 Australian Open and US Open titles, she now only needs the Roland Garros trophy for a career Grand Slam.
The result was the best win of Potapova's fledgling career, and the 18-year-old will face either fellow teen Marketa Vondrousova or Wang Yafan in round two.
A disappointed Kerber said: “She really played good. I tried my best. I was able to practise the last few days really good, but it was not really a long clay-court preparation with everything.
“I was happy to at least go on court, playing a match. Of course it’s not like I hoped for.”
WOMEN’S FIRST-ROUND RESULTS
Anastasia Potapova (Rus) bt (5) Angelique Kerber (Ger) 6-4 6-2, (31) Petra Martic (Cro) bt Ons Jabeur (Tun) 6-1 6-2, Johanna Larsson (Swe) bt Magdalena Rybarikova (Svk) 6-3 6-4, (19) Garbine Muguruza (Esp) bt Taylor Townsend (USA) 5-7 6-2 6-2, Oscar Otte (Ger) bt Malek Jaziri (Tun) 6-3 6-1 4-6 6-0, Kristina Kucova (Svk) bt Svetlana Kuznetsova (Rus) 6-4 6-2.