South Africas Kevin Anderson returns the ball to Austria's Dominic Thiem during the Mubadala World Tennis Championship 2017 match in Abu Dhabi, on December 29, 2017. / AFP PHOTO / NEZAR BALOUT (Photo credit should read NEZAR BALOUT/AFP/Getty Images)
South Africas Kevin Anderson returns the ball to Austria's Dominic Thiem during the Mubadala World Tennis Championship 2017 match in Abu Dhabi, on December 29, 2017. / AFP PHOTO / NEZAR BALOUT (Photo credit should read NEZAR BALOUT/AFP/Getty Images)