Nick Kyrgios celebrates his Citi Open title with his team on Sunday in Washington, D.C.

Nick Kyrgios wins his second ATP Tour title of the year at the Citi Open.

Daniil Medvedev is going for his second ATP 500 title in Washington, D.C.

Raven Klaasen and Michael Venus level their FedEx ATP Head2Head series at 1-1 against Jean-Julien Rojer and Horia Tecau.

Raven Klaasen and Michael Venus claim their second ATP 500 title of the season at the Citi Open on Sunday.

Nick Kyrgios celebrates reaching the Citi Open final in Washington, D.C., on Saturday night with his new friend/advisor.

Nick Kyrgios is going for his second ATP Tour title of 2019 at the Citi Open in Washington, D.C.

Jamie and Andy Murray didn't drop serve in their quarter-final doubles match at the Citi Open, but it wasn't enough to prevail.

Stefanos Tsitsipas is through to the Citi Open semi-finals without dropping a set.

Andy Murray and Jamie Murray saw their Citi Open doubles reunion come to an end in the quarter-finals.

Lucky loser Norbert Gombos took Kevin Anderson's vacant position in the Citi Open main draw.

Stefanos Tsitsipas is through to the Citi Open quarter-finals without dropping a set.

Marin Cilic beats Felix Auger-Aliassime in straight sets in their first FedEx ATP Head2Head meeting.

Felix Auger-Aliassime picks up his 29th win of the year against Reilly Opelka at the Citi Open.

After his early Wimbledon loss, Stefanos Tsitsipas read about his tennis idol, Roger Federer.

Stefanos Tsitsipas will try to improve upon his 2018 semi-final appearance in Washington this week.

Stefanos Tsitsipas is going for his third ATP Tour title of the season in Washington.

Jean-Julien Rojer and Horia Tecau look to win a second title in Washington.

Felix Auger-Aliassime wins his first FedEx ATP Head2Head meeting with American Reilly Opelka on Wednesday at the Citi Open in Washington, D.C.

Jamie and Andy Murray share the court for the first time in three years at the Citi Open.

Jo-Wilfried Tsonga hits 44 winners to reach the third round at the Citi Open in Washington, D.C., on Tuesday.

ATP Tour stars, including, from right to left, Stefanos Tsitsipas, Nick Kyrgios, Juan Sebastian Cabal and Robert Farah, pay tribute to former ATP Tour champion Peter McNamara on Monday at the Citi Open.

Jo-Wilfried Tsonga wins his first match since Wimbledon on Monday at the CIti Open in Washington, D.C.

Nick Kyrgios and Stefanos Tsitsipas lose to top-seeded Juan Sebastian Cabal and Robert Farah on their team debut in Washington, D.C.

Andy Murray is competing in doubles with his brother Jamie this week at the CIti Open in Washington, D.C.

Sixth seed Marin Cilic owns a 6-3 record at the Citi Open.

Apostolos Tsitsipas says he feels fortunate that his son Stefanos allows him to be his coach.

Top seed Stefanos Tsitsipas, making his second appearance in Washington, D.C., practises on opening weekend at the Citi Open.

Apostolos Tsitsipas and his son Stefanos have travelled together since Stefanos was 12 years old.

Jamie Murray and Andy Murray reunite on the doubles court for the first time in three years at the Citi Open.

John Isner taking direction from executive chef Jerome Grant at the Citi Taste of Tennis in Washington, D.C.