US
Muchova silenced a capacity crowd to beat Olympic champion Zheng in straight sets
Sinner, Alcaraz race through to the next stage
They push each other to the limit in the latest chapter of burgeoning rivalry
The Italian world number one twice tested positive for banned substance clostebol
Sabalenka and Zheng are on course to meet in the semi-final
Swiatek, Sinner both qualify for 2nd round after beating their opponents
World number eight overcame Frenchman Luca Van Assche 4-6, 6-3, 6-4, firing 15 aces
Sixth seed outlasted Baptiste 7-6 (8/6), 7-6 (7/3) to reach second round
Despite winning 24 Grand Slam titles, the Serbian tennis star has yet to secure an Olympic gold
Discussions on officiating fairness in tennis intensified following Gauff's advocacy for video review and fair play