Cornet has only reached the fourth round at a Grand Slam once before, in Australia five years ago
It is only the third time in 15 visits to Wimbledon that Williams has lost so early. She has not been past the fourth round of a Grand Slam in 2014. Cornet, 24, had never before beaten a top-20 player at a Grand Slam.
"I just cannot believe it," she told BBC Sport. "Three years ago I couldn't play on grass, I was so bad, but now I have beaten Serena, the world number one on her own court.
