America's Bethanie Mattek-Sands was stretchered off court screaming in pain after suffering a serious knee injury during her second-round women's singles match at Wimbledon on Thursday.
Mattek-Sands was playing Romania's Sorana Cirstea on outside Court 17 when she appeared to slip as she approached the net at the beginning of the third set then collapsed awkwardly to the grass.
After a moment's silence she suddenly screamed out in pain, then shouted "help me," clutching her right leg.
Cirstea approached her then looked shocked as Mattek-Sands continued to cry out in pain as everybody around the court initially seemed stunned.
Medical personnel then attended and she was treated by doctors on the court for more than 20 minutes on court, and given oxygen and an injection.
Still clearly in pain she continued to scream out. "It hurts, hurts so much."
The 32-year-old has won three grand slam doubles titles with Czech Lucie Safarova, who was crying courtside during the incident, and if she had won at Wimbledon would have held all four at the same time.
The Woman's Tennis Association said Mattek-Sands had suffered an acute knee injury and had been taken straight to hospital.