New York - Canada's Eugenie Bouchard withdrew from the US Open on Sunday after failing to recover from the head injury she suffered in a freak locker room fall, organisers said.
"Eugenie Bouchard is withdrawing from the women's singles competition at the 2015 US Open due to a concussion," said a statement.
The 21-year-old had been due to face Italy's Roberta Vinci later Sunday for a spot in the quarter-finals.
Bouchard, the poster girl of the women's game, had already pulled out of the women's doubles and mixed doubles on Saturday.
She suffered the injury on Friday night when she slipped and fell in the women's locker room.US Open results on Sunday, the seventh day of the 2015 tournament at Flushing Meadows (x denotes seeded player):
Novak Djokovic (SRB x1) bt Roberto Bautista Agut (ESP x23) 6-3, 4-6, 6-4, 6-3
Feliciano Lopez (ESP x18) bt Fabio Fognini (ITA x32) 6-3, 7-6 (7/5), 6-1
Jo-Wilfried Tsonga (FRA x19) bt Benoit Paire (FRA) 6-4, 6-3, 6-4
Marin Cilic (CRO x9) bt Jeremy Chardy (FRA x27) 6-3, 2-6, 7-6 (7/2), 6-1
Serena Williams (USA x1) bt Madison Keys (USA) 6-3, 6-3
Venus Williams (USA x23) bt Anett Kontaveit (EST) 6-2, 6-1
Kristina Mladenovic (FRA) bt Ekaterina Makarova (RUS x13) 7-6 (7/2), 4-6, 6-1
Roberta Vinci (ITA) bt Eugnie Bouchard (CAN x25) - walkover