2016 Rio Olympics - Tennis - Preliminary - Women's Singles Third Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Serena Williams (USA) of USA shakes hands with Elina Svitolina (UKR) of Ukraine after losing their match. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Third Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Monica Puig (PUR) of Puerto Rico reacts during match against Garbine Muguruza (ESP) of Spain. REUTERS/Toby Melville

2016 Rio Olympics - Golf - Preliminary - Training session - Olympic Golf Course - Rio de Janeiro, Brazil 09/08/2016. Rickie Fowler (USA) of the United States hits a tee shot during a practice round. REUTERS/Andrew Boyers

2016 Rio Olympics - Golf - Preliminary - Training session - Olympic Golf Course - Rio de Janeiro, Brazil 09/08/2016. Bubba Watson (USA) of the United States hits a pitch shot from the fairway during a practice session. REUTERS/Andrew Boyers

2016 Rio Olympics - Golf - Preliminary - Training session - Olympic Golf Course - Rio de Janeiro, Brazil 09/08/2016. Rickie Fowler (USA) (R) of the United States and compatriot Bubba Watson watch Fowler's shot during a practice session. REUTERS/Andrew Boyers

2016 Rio Olympics - Golf - Preliminary - Training session - Olympic Golf Course - Rio de Janeiro, Brazil 09/08/2016. Matt Kuchar (USA) of the United States hits a tee shot during a practice session. REUTERS/Andrew Boyers

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Third Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Garbine Muguruza (ESP) of Spain in action against Monica Puig (PUR) of Puerto Rico. REUTERS/Kevin Lamarque

2016 Rio Olympics - Tennis - Preliminary - Women's Singles Third Round - Olympic Tennis Centre - Rio de Janeiro, Brazil - 09/08/2016. Monica Puig (PUR) of Puerto Rico celebrates after winning her match against Garbine Muguruza (ESP) of Spain. REUTERS/Toby Melville