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

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