Roger Federer and Rafael Nadal resume their US Open campaigns tomorrow while the race to be women's world number one is down to three players.
Top seed Nadal plays Argentina's Leonardo Mayer in the third round.
Federer, seeded second, is up against Spain's Feliciano Lopez.
Karolina Pliskova must beat Shuai Zhang to hold on to her top ranking.
Ukraine's fourth seed Elina Svitolina also has her sights set on the number one ranking, and she faces American Shelby Roger.
Spain's Garbine Muguruza is the other woman in with a chance of topping the rankings at the end of the tournament, and the Wimbledon champion next plays on Sunday against Petra Kvitova.
Five‑time champion Federer and two‑time winner Nadal are still in line to meet in the semifinals, although neither man has yet been at their best.
Source: BBC
