Estonia's Jurgen Zopp returns the ball to Bulgaria's Grigor Dimitrov during the ATP Stockholm Open tennis tournament in Stockholm on October 20, 2016. / AFP / JONATHAN NACKSTRAND (Photo credit should read JONATHAN NACKSTRAND/AFP/Getty Images)
Estonia's Jurgen Zopp returns the ball to Bulgaria's Grigor Dimitrov during the ATP Stockholm Open tennis tournament in Stockholm on October 20, 2016. / AFP / JONATHAN NACKSTRAND (Photo credit should read JONATHAN NACKSTRAND/AFP/Getty Images)