(TIML NEWS) American player Bethanie Mattek-Sands suffered a devastating injury Thursday at Wimbledon, collapsing in a heap on the court and sending shouts of anguish echoing across the grounds.

Mattek-Sands was charging the net when her leg buckled and she grabbed for her right knee.

As horrified spectators looked on, she began to shout: “Help me! Help me!”

Help eventually arrived to the outer Court 17, and it was nearly 20 minutes before medical personnel removed Mattek-Sands from the court via stretcher to a waiting ambulance.

Mattek-Sands, 32, was in the third set of a second-round singles match against Sorana Cirstea.

Along with partner Lucie Safarova, Mattek-Sands is the reigning doubles champion in three of the four majors and was vying for a non-calendar-year Grand Slam at Wimbledon.