Serena Williams shows off her pert posterior in red swimsuit as tennis champion enjoys some down time in Texas

Serena Williams wore a red swimsuit as she enjoyed some down time on Sunday October 4 at San Marco river in Texas.

The 34-year-old tennis ace was joined by TV star Colton Haynes and a female pal during her outing.

Williams won't be taking part at the China Open in Beijing and the WTA Tour Finals in Singapore this year again so she can recover from injuries. She is expected to feature at the Australian Open in January 2016.