The 39-year-old Swiss won the title at Melbourne Park in 2014, defeating Rafael Nadal.
It was the second major sporting event for Taylor Swift and Travis Kelce in New York City over the past five-plus weeks.
Chelsea boss Enzo Maresca said Cole Palmer is not 'completely fit' for their London derby against Arsenal in the Premier League.
The Padma Shri awardee said competing at the Olympics was her childhood dream and missing the showpiece for two consecutive editions has been hurtful.
In the women's draw, the wildcard entry Zhang, who on Wednesday won her first singles match in more than 600 days, stunned US Open semi-finalist Emma Navarro 6-4, 6-2.