Czech Republic's Petra Kvitova watches tennis balls as she plays Belgium's Greet Minnen during their first round match of the French Open tennis tournament at the Roland Garros stadium Sunday, May 30, 2021 in Paris. (AP Photo/Thibault Camus)

Czech Republic's Petra Kvitova returns the ball to Belgium's Greet Minnen during their first round match of the French Open tennis tournament at the Roland Garros stadium Sunday, May 30, 2021 in Paris. (AP Photo/Thibault Camus)