New York - World number one Novak Djokovic played Cupid to help a close friend propose to his girlfriend at the US Open on the tournament's showpiece Arthur Ashe Stadium.
Djokovic was hitting with Germany's Tommy Haas while longtime friend Kirk Spahn watched from the sidelines and girlfriend Jenny Alden acted as umpire.
Once the session stopped, Spahn climbed up steps of the official's chair to place an engagement ring on Alden's finger.
"Look what happened a few days ago on my practice session. I am very excited for you guys and glad I had a role in this wonderful surprise! Congratulations Kirk Spahn and Jenny," wrote Djokovic on his Facebook page Thursday.
Alden, who has undergone brain surgery, tweeted her thanks to the Serb star.
"Ah Ha!! Thank you @DjokerNole for making my proposal such a special one! facebook.com/djokovic.offic...#IGotPUNKED! #Engaged#MustWatch!," she wrote.