NEW YORK — Tennis star Eugenie Bouchard took the witness stand on Wednesday in her negligence lawsuit against the United States Tennis Association, describing how she slipped and fell on a wet locker room floor at the U.S. Open in 2015.

Bouchard had just played in a mixed doubles match when she returned to the locker room at the Billie Jean King National Tennis Center in Queens shortly after 10 p.m. Minutes later, she fell on the tile floor of a physiotherapy room inside the locker room.

She told a jury in federal court in Brooklyn that she had taken two steps into the training area en route to take an ice bath when she lost her footing "and hit the back of my head on the floor." She recalled being in "shock" as she found herself "staring at the ceiling."

The 23-year-old Canadian player testified she also felt a burning sensation on her skin from what her lawyers say was a powerful cleaning solution left on the floor.

A lawsuit filed in 2015 accused the USTA of failing to take proper steps to warn Bouchard and other players that the floor was wet. Lawyers for the USTA counter that she should have known not to enter the area without being accompanied by a trainer or other tournament personnel and that the cleaning crew believed all the players had left for the night.

The lawsuit says the fall left Bouchard with a concussion and a "serious head injury." She says she was forced to withdraw from the U.S. Open, where she was still in contention in singles and doubles, and from subsequent tournaments in China and Japan.

Lawyers for Bouchard, once ranked No. 5 in the world and a Wimbledon finalist in 2014, claim the fall and the injury in the locker room have hurt her career. She's currently ranked No. 116.

Her lawsuit seeks unspecified damages.