2016 Rio Olympics - Basketball - Preliminary - Men's training session - Carioca Arena 1 - Rio de Janeiro, Brazil - 04/08/2016. Klay Thompson (USA) of USA shoots during practice. REUTERS/Pool

2016 Rio Olympics - Basketball - Preliminary - Men's training session - Carioca Arena 1 - Rio de Janeiro, Brazil - 04/08/2016. Kevin Durant (USA) of USA attends practice. REUTERS/Jim Young

2016 Rio Olympics - Basketball - Men's training session - Carioca Arena 1 - Rio de Janeiro, Brazil - 04/08/2016. Brazil's Mens basketball team trains. REUTERS/Jim Young

Russian Olympic Committee (ROC) chief Alexander Zhukov attends a news conference ahead of Russian Olympic team departure to Rio 2016 Olympic Games in Moscow, Russia, July 26, 2016. REUTERS/Maxim Shemetov

Russian Olympic Committee (ROC) chief Alexander Zhukov addresses Russia's Olympic team members during a farewell ceremony before the national team's departure to 2016 Rio Olympics at Sheremetyevo International Airport outside Moscow, Russia, July 28, 2016. REUTERS/Sergei Karpukhin

2016 Rio Olympics - Tennis training - Olympic Tennis Centre - Rio de Janeiro, Brazil - 04/08/2016. Novak Djokovic (SRB) of Serbia trains. REUTERS/Toby Melville

2016 Rio Olympics - Rio de Janeiro, Brazil - 04/08/2016. Tennis player Novak Djokovic (SRB) of Serbia (on R) poses for a picture during the team welcoming ceremonies. REUTERS/Ivan Alvarado

2016 Rio Olympics - Tennis training - Olympic Tennis Centre - Rio de Janeiro, Brazil - 04/08/2016. Juan Martin Del Potro (ARG) of Argentina trains. REUTERS/Kevin Lamarque