Spain's Rafael Nadal plays a shot against Egor Gerasimov of Belarus in the first round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Japan's Yoshihito Nishioka celebrates winning his first round match of the French Open tennis tournament against Canada's Felix Auger-Aliassime at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Christophe Ena)

Serena Williams of the U.S. screams in the first round match of the French Open tennis tournament against Kristie Ahn of the U.S. at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Serena Williams of the U.S. walks to her bench after defeating Kristie Ahn of the U.S., left, in the first round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Austria's Dominic Thiem reacts in the first round match of the French Open tennis tournament against Croatia's Marin Cilic at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Spectators watch Austria's Dominic Thiem and Croatia's Marin Cilic play their first round match of the French Open tennis tournament in center court Philippe Chatrier at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Croatia's Marin Cilic gestures in the first round match of the French Open tennis tournament against Austria's Dominic Thiem at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Petra Kvitova of the Czech Republic wipes her nose as an official, right, tests the balls in the first round match of the French Open tennis tournament against France's Oceane Dodin at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Serena Williams of the U.S. reacts after missing a shot against Kristie Ahn of the U.S. in the first round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Serena Williams of the U.S. plays a shot against Kristie Ahn of the U.S. in a near-empty center court Philippe Chatrier in the first round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Kristie Ahn of the U.S. plays a shot against Serena Williams of the U.S. in the first round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Alessandra Tarantino)

Spain's Rafael Nadal answers questions of journalist via a video connection in an empty press conference room after his first round match of the French Open tennis tournament at the Roland Garros stadium in Paris, France, Monday, Sept. 28, 2020. (AP Photo/Christophe Ena)