
Novak Djokovic of Serbia serves to David Goffin of Belgium 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)

Novak Djokovic of Serbia serves to David Goffin of Belgium 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)