The Western & Southern Open will not take place on Thursday amid protests against racial injustice.
Teams and players in North America boycotted several games across different sports on Wednesday over the police shooting of Jacob Blake, a black man, in Wisconsin.
Blake was repeatedly shot in the back by police, prompting nationwide protests within professional sports.
After two-time grand slam champion Naomi Osaka announced she would not play her Western & Southern Open semi-final against Elise Mertens scheduled for Thursday, the tournament was paused.
"As a sport, tennis is collectively taking a stance against racial inequality and social injustice that once again has been thrust to the forefront in the United States," a statement read.
"The USTA, ATP Tour, and WTA have decided to recognise this moment in time by pausing tournament play at the Western & Southern Open on Thursday, August 27.
"Play will resume on Friday, August 28."
It remains unclear if that means Osaka will take her place in the draw. The other women's semi-final is between Victoria Azarenka and Johanna Konta.
Novak Djokovic is due to face Roberto Bautista Agut in a men's semi, while Stefanos Tsitsipas is scheduled to take on Milos Raonic.