Diego Schwartzman, of Argentina, plays Karen Khachanov, of the Russian Olympic Committee, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Diego Schwartzman, of Argentina, plays Karen Khachanov, of the Russian Olympic Committee, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Karen Khachanov, of the Russian Olympic Committee, plays Diego Schwartzman, of Argentina, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Diego Schwartzman, of Argentina, reacts while playing Karen Khachanov, of the Russian Olympic Committee, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)

Karen Khachanov, of the Russian Olympic Committee, reacts while playing Diego Schwartzman, of Argentina, during the third round of the tennis competition at the 2020 Summer Olympics, Wednesday, July 28, 2021, in Tokyo, Japan. (AP Photo/Seth Wenig)