2019 US Open

NEW YORK, NEW YORK - AUGUST 26: Fans walk around the grounds during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Novak Djokovic of Serbia returns a shot during his men's singles first round match against Roberto Carballes Baena of Spain during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Novak Djokovic of Serbia returns a shot during his men's singles first round match against Roberto Carballes Baena of Spain during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Novak Djokovic of Serbia celebrates after winning his men's singles first round match against Roberto Carballes Baena of Spain during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Billie Jean King looks on during the opening night ceremony at Arthur Ashe Stadium on day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Maria Sharapova of Russia prepares to serve during her Women's Singles first round match against Serena Williams of the United States during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Emilee Chinn/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Maria Sharapova of Russia returns a shot during her Women's Singles first round match against Serena Williams of the United States during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Emilee Chinn/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Serena Williams of the United States returns a shot during her Women's Singles first round match against Maria Sharapova of Russia during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Serena Williams of the United States reacts during her Women's Singles first round match against Maria Sharapova of Russia during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Serena Williams of the United States shakes hands with Maria Sharapova of Russia after defeating her in her Women's Singles first round match during day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)

2019 US Open - Day 1

NEW YORK, NEW YORK - AUGUST 26: Serena Williams of the United States celebrates after defeating Maria Sharapova of Russia after their Women's Singles first round match 1on day one of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 26, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)