Four-time French Open champion Justine Henin's preparation for the Roland Garros Grand Slam event suffered a shuddering jolt with a defeat by France's Aravane Rezai in the Madrid Open first round on Sunday.
Henin won the Stuttgart title on clay last week and is considered a dangerous outsider in Paris later this month but her first serve was inconsistent and Rezai, the world number 22, took full advantage with a 4-6, 7-5, 6-0 win as the Belgian's game collapsed.
Henin beat Australia's Samantha Stosur in the final in Stuttgart last Sunday for her first title since she ended her 19-month self-imposed exile at the start of the year.
Maria Sharapova was another former World No 1 to fall at the first hurdle, the Russian 11th seed going down 6-4, 6-3 to Lucie Safarova of the Czech Republic.
"It's a struggle trying to find the rhythm," a philosophical Sharapova, who was playing her first tournament since pulling out of the Sony Ericsson Open in March with an elbow injury, said.
"I thought (Safarova) played really solid, good tennis and did everything she needed to win the match. More solid than me anyway," the 23-year-old added.
"I certainly had my chances in the match and a few balls here and there that I maybe would have made if I had the matches under my belt."
Safarova broke Sharapova's serve four times and the Czech is on course for a possible last-16 clash with sixth-seeded Russian Elena Dementieva.
"If you win against these top players, as I have the last couple of months, then you get your confidence and you realise you can be up there," the world number 35, who beat World No 2 Caroline Wozniacki in Stuttgart, said.
"My dream is to be top 10 and it's a lot about believing in yourself."