US Open 2021: Novak Djokovic will face Alexander Zverev in semi-final

US Open 2021: Novak Djokovic will face Alexander Zverev in semi-final https://ift.tt/eA8V8J Novak Djokovic will continue his bid to win all four Grand Slams in the same year against Olympic champion Alexander Zverev in Friday's US Open semi-final.