World No 1 will face Thiem after 6-3, 7-6 (4) victoryTop four players in world will contest semi-finalsNovak Djokovic defeated Alexander Zverev to set up a semi-final clash against
US Open champion Dominic Thiem at the Nitto ATP Finals.
For the second day in a row at London’s O2, one of the world’s top two
Tennis players found himself in a straight shoot-out for a place in the last four. And Djokovic emulated
Rafael Nadal, who beat Stefanos Tsitsipas, by seeing off 2018 champion Zverev 6-3 7-6 (4).