BEIJING, China - A teary-eyed Eugenie Bouchard retired from her opening match against Andrea Petkovic at the China Open due to dizziness on Monday, her first match since falling at the U.S. Open last month and suffering a concussion.

Bouchard slipped in the locker room after her third-round win against Dominika Cibulkova at the U.S. Open, falling backward and landing on the back of her head. She was forced to withdraw from the tournament, as well as subsequent tournaments in Tokyo and Wuhan.

The Canadian was trailing 6-2, 1-1 against Petkovic on Monday when she decided to call it quits.

Petkovic said after the match that Bouchard told her she felt very dizzy and that the effects of the concussion tend to "come back when she gets physically very active."