
John Isner of the United States returns the ball during the semifinal match of men's singles against Germany's Alexander Zverev at the Italian Open tennis tournament in Rome, Italy, May 20, 2017. John Isner lost 1-2. (Xinhua/Jin Yu)

John Isner of the United States returns the ball during the semifinal match of men's singles against Germany's Alexander Zverev at the Italian Open tennis tournament in Rome, Italy, May 20, 2017. John Isner lost 1-2. (Xinhua/Jin Yu)