2019 US Open

NEW YORK, NEW YORK - AUGUST 28: Novak Djokovic of Serbia returns a shot during his Men's Singles second round match against Juan Ignacio Londero of Argentina on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)

2019 US Open - Day 3

Juan Ignacio Londero of Argentina returns a shot during his Men's Singles second round match against Novak Djokovic of Serbia on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)

2019 US Open - Day 3

Novak Djokovic of Serbia returns a shot during his Men's Singles second round match against Juan Ignacio Londero of Argentina on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Clive Brunskill/Getty Images)

2019 US Open - Day 3

Ashleigh Barty of Australia returns a shot during her Women's Singles second round match against Lauren Davis of the United States on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 3

Lauren Davis of the United States returns a shot during her Women's Singles second round match against Ashleigh Barty of Australia on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 3

Venus Williams of the United States returns a shot during her Women's Singles second round match against Elina Svitolina of the Ukraine on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 3

Venus Williams of the United States reacts during her Women's Singles second round match against Elina Svitolina of the Ukraine on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)

2019 US Open - Day 3

Elina Svitolina of the Ukraine returns a shot during her Women's Singles second round match against Venus Williams of the United States on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 3

Venus Williams (L) of the United States shakes hands with Elina Svitolina of the Ukraine after losing to her in her Women's Singles second round match on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Matthew Stockman/Getty Images)

2019 US Open - Day 3

Roger Federer of Switzerland returns a shot during his Men's Singles second round match against Damir Dzumhur of Bosnia and Herzegovina on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

2019 US Open - Day 3

Damir Dzumhur of Bosnia and Herzegovina returns a shot during his Men's Singles second round match against Roger Federer of Switzerland on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

2019 US Open - Day 3

Roger Federer of Switzerland reacts during his Men's Singles second round match against Damir Dzumhur of Bosnia and Herzegovina on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Elsa/Getty Images)

2019 US Open - Day 3

Kei Nishikori of Japan returns a shot during his Men's Singles second round match against Bradley Klahn of the United States on day three of the 2019 US Open at the USTA Billie Jean King National Tennis Center on August 28, 2019 in the Flushing neighborhood of the Queens borough of New York City. (Photo by Al Bello/Getty Images)

TENNIS-US-OPEN

Karolina Pliskova of the Czech Republic plays against Mariam Bolkvadze of Georgia during their Round Two Women's Singles match at the 2019 US Open at the USTA Billie Jean King National Tennis Center in New York on August 28, 2019. (Photo by TIMOTHY A. CLARY / AFP) (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)

TENNIS-US-OPEN

Mariam Bolkvadze of Georgia plays against Karolina Pliskova of the Czech Republic during their Round Two Women's Singles match at the 2019 US Open at the USTA Billie Jean King National Tennis Center in New York on August 28, 2019. (Photo by TIMOTHY A. CLARY / AFP) (Photo credit should read TIMOTHY A. CLARY/AFP/Getty Images)