
David Goffin of Belgium returns the ball to Novak Djokovic of Serbia during the quarterfinal match of 2017 Monte-Carlo Masters in Roquebrune-Cap-Martin, on April 21, 2017. David Goffin won 2-1. (Xinhua/Stephane Danne)

David Goffin of Belgium returns the ball to Novak Djokovic of Serbia during the quarterfinal match of 2017 Monte-Carlo Masters in Roquebrune-Cap-Martin, on April 21, 2017. David Goffin won 2-1. (Xinhua/Stephane Danne)