Playing Sorana Cîrstea in the second round of the Wimbledon singles, Mattek-Sands was running to the net at the beginning of the third set when she collapsed in agony, clutching at her right knee. She shouted out a large number of swear words for which she later apologized. She was treated on the court before being rushed to a local hospital with an "acute knee injury" which was later revealed to be a dislocated kneecap and ruptured patellar ligament, for which surgery was required. Mattek-Sands had suffered a torn medial collateral ligament on the same knee in September 2013.