Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - February 27, 2019 Spain's Fernando Verdasco reacts during his Quarter Final match against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Greece's Stefanos Tsitsipas in action during his semi final match against France's Gael Monfils REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer signs his autograph for fans after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - February 27, 2019 Switzerland's Roger Federer with Spain's Fernando Verdasco after their Quarter Final match REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - February 27, 2019 Spain's Fernando Verdasco reacts during his Quarter Final match against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Croatia's Borna Coric reacts during his semi final match against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Christopher Pike

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer celebrates winning the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer and Greece's Stefanos Tsitsipas pose with their trophies after the Final REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - February 27, 2019 Switzerland's Roger Federer embraces Spain's Fernando Verdasco after their Quarter Final match REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 France's Gael Monfils in action during his semi final match against Greece's Stefanos Tsitsipas REUTERS/Christopher Pike

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 France's Gael Monfils in action during his semi final match against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Croatia's Borna Coric in action during his semi final match against Switzerland's Roger Federer REUTERS/Christopher Pike

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer celebrates after winning his semi final match against Croatia's Borna Coric REUTERS/Christopher Pike

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - February 28, 2019 Poland's Hubert Hurkacz in action during his quarter final match against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas in action during the Final against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer celebrates winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer celebrates with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 France's Gael Monfils in action during his semi final match against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 France's Gael Monfils in action during his semi final match against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Christopher Pike

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer celebrates after winning his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - February 28, 2019 Poland's Hubert Hurkacz in action during his quarter final match against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer celebrates winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer and Greece's Stefanos Tsitsipas pose with their trophies after the Final REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Great Britain's Joe Salisbury and Rajeev Ram of the U.S. pose with their trophies after winning the Men's Doubles Final REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 France's Gael Monfils in action during his semi final match against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Croatia's Borna Coric in action during his semi final match against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Christopher Pike

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 1, 2019 Switzerland's Roger Federer in action during his semi final match against Croatia's Borna Coric REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer in action during the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer reacts during the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Greece's Stefanos Tsitsipas poses with his runners up trophy after losing the Final against Switzerland's Roger Federer REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer celebrates with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Ahmed Jadallah

Tennis - ATP 500 - Dubai Tennis Championships - Dubai Duty Free Tennis Stadium, Dubai, United Arab Emirates - March 2, 2019 Switzerland's Roger Federer poses with the trophy after winning the Final against Greece's Stefanos Tsitsipas REUTERS/Satish Kumar Subramani