World number 271 Jerome Haehnel produced the shock result of the year by beating Andre Agassi in the French Open first round.
Frenchman Haehnel beat the sixth seed 6-4 7-6 (7-4) 6-3 to delight the home crowds at Roland Garros.
Haehnel, 23, had never played a tour level match before this victory.
Agassi, who has won every Grand Slam in a superb career, had played just one warm-up event in the build-up to Paris, again suffering defeat to an outsider.
His loss will lead to increased speculation that the 34-year-old will retire at the end of the season.
Asked if he would return to Roland Garros, the eight-times Grand Slam champion replied: "Hard to say.
"You want to come back, but you just don't know. I don't know. It's a year away, and that's a long time for me right now.
"The chances get less every year, that's for sure."
The American was playing his 16th French Open and aiming to win his 800th career match but instead he was given the run-around by an opponent who spends his career on the satellite tour.
"I never got comfortable out there," he admitted.
"I couldn't control the ball, couldn't put it where I wanted and found myself in the wrong parts of the court.
"I wish I could give you an excuse. There is no explanation for hitting the ball that way. Usually, shot selection is not a problem for me."
Agassi, who had played just one clay court match all season and lost it to unheralded Nenad Zimonjic last week, hit 39 winners compared to Haehnel's 27.
But he was unable to make the pressure count on the big points breaking his opponent's serve just once.
Haehnel admitted to battling nerves as he closed out his famous victory.
"I was very nervous," he said: "I tried to keep the ball in and take my time because the courts were very fast."
The Frenchman will now either face compatriot Michael Llodra or Germany's Alexander Popp in the next round and is a possible last-16 foe for British number one Tim Henman, who had a five-set win on Monday.