Former champion Ana Ivanovic slumped to a 7-6, 0-6, 6-2 first round defeat to unheralded Swede Johanna Larsson at the French Open on Tuesday.
The 20th-seeded Serb, who withdrew from last week's Strasbourg International with a wrist injury, lacked consistency against the world number 64.
Ivanovic, who topped the world rankings in 2008 when she won at Roland Garros, seemed to have found her form when she rolled through a one-sided second set despite still battling to stem the unforced errors.
She went off the boil again in the sunshine on court Suzanne Lenglen in the decider and bowed out after one hour and 49 minutes when she netted a routine forehand.
Meanwhile, fighting back tears, Virginie Razzano sought comfort on court Philippe Chatrier on Tuesday, eight days after her coach and fiance died of a brain tumour.
The Frenchwoman lost 6-3, 6-1 to Australian Jarmila Gojdasova in the first round, but showed courage and dignity and received a compassionate pat on the back from her opponent at the end of an emotional match.
"I grabbed all my courage. I don't have much. I'm very fragile. I feel lonely, and even though there are many people around me supporting me I still have the strength in me that keeps me standing up and moving on step by step," a watery-eyed Razzano told reporters in her post-match press conference.
Stephane Vidal died at the age of 32 last Monday after losing his battle against a long-term brain tumour.
Former world number one Maria Sharapova started her campaign in convincing fashion, dismissing Croatian Mirjana Lucic 6-3, 6-0.
The Russian seventh seed, who won the Rome International this month, broke in the seventh game and never looked back.
Sharapova, wearing a yellow dress on another sunlit day on court Philippe Chatrier, produced some deft tennis and looked fully fit.
She next faces French teenager Caroline Garcia.