Bethanie Mattek-Sands Photo: Kirsty Wigglesworth/AP

America's Bethanie Mattek-Sands suffered a horror knee injury at Wimbledon on Thursday which left her screaming and crying in pain in the middle of the court.

The 32-year-old collapsed to the ground after damaging her right knee as she approached the net in the first game of the deciding set against Romania's Sorana Cirstea on Court 17.

"Please help me, please, please," screamed the 32-year-old in scenes so distressing that television cameras panned away from the stricken player.

Mattek-Sands's husband Justin tried to console his wife as medics arrived, while Cirstea was distraught and in tears.

After lying prone on the ground for around 20 minutes, Mattek-Sands was eventually stretchered away.

Mattek-Sands's doubles partner, Lucie Safarova, with whom she shares the world number one ranking as well as four Grand Slam titles, also arrived at the scene in tears.

"Really wish they would turn the cameras and mics off on Bethanie's court," tweeted fellow American player Madison Keys as the shocking images and sounds of her compatriot were played out on the tournament TV screens.