World number one beat Swiss Masarova 7-5, 6-1

The 38-year-old Serb beat Learner Tien 6-1, 7-6 (7/3), 6-2 in 2hr 25min

The tournament begins from August 25-30

The men's draw will also see former world number one Novak Djokovic

Italian opens his campaign in the first round against Vit Kopriva

The 38-year-old has not played since Wimbledon semi-final defeat last month

The following are some of the other contenders for the women's singles title at the U.S. Open, which begins on Sunday

The 23-year-old took an eight-month break from the sport to focus on her mental health

Defending champions beat Iga Swiatek and Casper Ruud 6-3 5-7 10-6 in revamped event

The Pole pairing with Ruud defeated Madison Keys and Frances Tiafoe