Serena Williams practices with Venus, pulls parking prank amid Citi Open stopover

WATCH: The Break—Citi Open Edition

WASHINGTON—Even when Serena isn’t on court, she’s still serving.

Such has been the case for the 23-time Grand Slam champion as she enjoys a breezy week at the Citi Open, supporting sister Venus ahead of her first singles match in over a year.

Serena hasn’t gone totally tennis-free despite her absence from the Washington, D.C. draw, playing hitting partner to big sis over the weekend.

The sisters thrilled fans with the public practice session as Venus readies to face Canada’s Rebecca Marino under the Stadium court lights.

Though she made an unexpected appearance in Wimbledon’s mixed doubles draw last month, Venus hasn’t flown solo since she played a pre-US Open event in Chicago last August.

After getting Venus warmed up, Serena cooled down with good friend and Citi Open chairman Mark Ein, taking in some of the capital’s most memorable sites:

Serena has indeed left her mark on D.C., including Ein’s parking spot in a prank immortalized on Instagram Monday morning.

All of this was enough to get Serena trending on Twitter!

Williams also last played at Wimbledon, enduring an emotional defeat to Frenchwoman Harmony Tan, but is set to make a return to action in Toronto for the National Bank Open.

In the meantime, let it be known, Citi Open, that Serena was here.