Doha, 30 Nov 2019 Three-time Grand Slam champion Stan Wawrinka of Switzerland and 2012 champion Jo-Wilfried Tsonga are among the stars set to kick start their season on the courts of the Khalifa International Tennis & Squash Complex at the Qatar ExxonMobil Open 2020 to be held from January 6 to 11 in Doha. In...