For the occasion, Markle wore a J.Crew blue jean button-up dress with a light grey jacket. Her dark locks were down and slightly tousled, and her makeup was soft and natural.
The royal mom was all smiles as she made her way to her seat, which was behind Williams' husband, Alexis Ohanian, and in front of Vogue Editor in Chief Anna Wintour.
In addition to Markle, Williams has had some high-profile cheerleaders at the U.S. Open, including Gigi Hadid and Priyanka Chopra.
The trip from London to New York City marks the Duchess of Sussex’s first trip out of the country without her and Prince Harry's son, Archie, since the little cutie’s birth in early May. This also marks her return to NYC following her baby shower which was held there and hosted by Williams.
After her quick NYC getaway, Markle is next set to travel to South Africa on an official royal tour with Prince Harry and 5-month-old Archie. The 10-day trip will have Markle focusing on women in the region and making efforts in higher education.