Reigning Wimbledon champion and US Open 14-time Grand Slam champion Serena Williams turned her left ankle during a doubles match alongside her sister Venus on Wednesday at the Grand Slam event.
There was no immediate indication regarding the extent of the injury from Williams but she was treated twice for the injury and played with a bandage on her ankle after trainers examined it.
While it was a setback, the Olympic gold-medal US duo cruised past compatriots Lindsay Lee-Waters and Megan Moulton-Levy 6-4, 6-0 in 63 minutes to reach the second round of the women's doubles tournament.
Serena and Venus Williams won the US Open women's doubles crown in 1999 and 2009.
Serena will face Spain's Maria Jose Martinez Sanchez in the women's singles second round on Thursday.