Novak Djokovic of Serbia reacts during his semifinal match against Alexander Zverev of Germany during the match Tokyo 2020 Olympics Tennis Men's Singles Semifinal at Ariake Tennis Park, Tokyo, Japan, July 30, 2021. Novak Djokovic was beaten 1-6 6-3 6-1 by Germany's Alexander Zverev in the semi-finals of the men's singles at the Tokyo Games. REUTERS/Mike Segar

Novak Djokovic of Serbia in action during his semifinal match against Alexander Zverev of Germany during the match Tokyo 2020 Olympics Tennis Men's Singles Semifinal at Ariake Tennis Park, Tokyo, Japan, July 30, 2021. REUTERS/Mike Segar

Novak Djokovic of Serbia in action during his semifinal match against Alexander Zverev of Germany during the match Tokyo 2020 Olympics Tennis Men's Singles Semifinal at Ariake Tennis Park, Tokyo, Japan, July 30, 2021. REUTERS/Mike Segar

Novak Djokovic of Serbia in action during his semifinal match against Alexander Zverev of Germany during the match Tokyo 2020 Olympics Tennis Men's Singles Semifinal at Ariake Tennis Park, Tokyo, Japan, July 30, 2021. REUTERS/Mike Segar

Novak Djokovic of Serbia in action during his semifinal match against Alexander Zverev of Germany during the match Tokyo 2020 Olympics Tennis Men's Singles Semifinal at Ariake Tennis Park, Tokyo, Japan, July 30, 2021. REUTERS/Mike Segar

Novak Djokovic of Serbia reacts during his semifinal match against Alexander Zverev of Germany during the match Tokyo 2020 Olympics Tennis Men's Singles Semifinal at Ariake Tennis Park, Tokyo, Japan, July 30, 2021. REUTERS/Mike Segar