 Complete the following phrase:  He has reached four Grand Slam singles finals in his career to date, winning three: the 2014 Australian Open, the 2015 French Open and the 2016 US Open; each time he defeated the reigning world No. 1 in the championship match Rafael Nadal once and Novak Djokovic twice, respectively. In doubles and team tennis for Switzerland, he has won a gold medal in the 