2016 Rio Olympics - Tennis - Preliminary - Men's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Evgeny Donskoy (RUS) of Russia reacts during his match against David Ferrer (ESP) of Spain. REUTERS/Toby Melville

2016 Rio Olympics - Tennis - Preliminary - Men's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Andy Murray (GBR) of United Kingdom celebrates after winning his match against Juan Monaco (ARG) of Argentina. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Men's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Andy Murray (GBR) of United Kingdom celebrates after winning his match against Juan Monaco (ARG) of Argentina. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 08/08/2016. Alize Cornet (FRA) of France in action against Serena Williams (USA) of USA. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 08/08/2016. Alize Cornet (FRA) of France reacts during her match against Serena Williams (USA) of USA. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 08/08/2016. Alize Cornet (FRA) of France in action against Serena Williams (USA) of USA. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 08/08/2016. Alize Cornet (FRA) of France reacts during her match against Serena Williams (USA) of USA. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Second Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 08/08/2016. Serena Williams (USA) of USA in action against Alize Cornet (FRA) of France. REUTERS/Kevin Lamarque