New York - Novak Djokovic marched into the US Open fourth round on Saturday before happily being upstaged by a precocious, nine-year-old pop singer.
Djokovic had defeated Sam Querrey 6-3, 6-2, 6-2 and then batted off a series of routine post-match questions from the media.
But he then invited Zia Uehling, the daughter of a family friend, onto the platform to perform her impromptu act.
"She's a prodigy, a future star, and this is a very valuable experience for her," said Djokovic.
"In a few years time she will be a big star and she'll be up on this stage."
Zia -- "I have written five songs....and I have about two books that I'm working on right now" -- then rattled off one of her own compositions to the watching media.
"I will sing an original song I wrote called African Sun. I wrote this song to give hope to the children in Africa. I never really play without my guitar, so I'll give it a try."
Zia is the daughter of Peter Uehling, a former pro and close friend of Djokovic since the world number one's teenage years.
The Serb stays at the Uehling house at Alpine, New Jersey, when he is at the US Open.
"Novak is a really nice guy. We all love him and we all want him to win. I try and watch his matches here but sometimes my mom says it's too late," said Zia, who has music in the blood as her mother was a backing singer with US rocker Cyndi Lauper and British punk band Siouxsie and the Banshees.
The star-struck youngster even benefitted from Lauper's professional advice.
"I asked her what the secret was and she said 'practice, practice, practice'."
Was she hopeful of following Djokovic into tennis when she was older?
"I played tennis but I told my dad that I had this need to sing," she said.Results on Saturday from the sixth day of the US Open, the final Grand Slam tournament of 2014 (x denotes seeded player):
Novak Djokovic (SRB x1) bt Sam Querrey (USA) 6-3, 6-2, 6-2
Philipp Kohlschreiber (GER x22) bt John Isner (USA x13) 7-6 (7/4), 4-6, 7-6 (7/2), 7-6 (7/4)
Jo-Wilfried Tsonga (FRA x9) bt Pablo Carreno-Busta (ESP) 6-4, 6-4, 6-4
Andy Murray (GBR x8) bt Andrey Kuznetsov (RUS) 6-1, 7-5, 4-6, 6-2
Stan Wawrinka (SUI x3) bt Blaz Kavcic (SLO) - walkover
Tommy Robredo (ESP x16) bt Nick Kyrgios (AUS) 3-6, 6-3, 7-6 (7/4), 6-3
Kei Nishikori (JPN x10) bt Leonardo Mayer (ARG x23) 6-4, 6-2, 6-3
Milos Raonic (CAN x5) bt Victor Estrella (DOM) 7-6 (7/5), 7-6 (7/5), 7-6 (7/3)
Serena Williams (USA x1) bt Varvara Lepchenko (USA) 6-3, 6-3
Kaia Kanepi (EST) bt Carla Suarez Navarro (ESP x15) 7-5, 6-0
Flavia Pennetta (ITA x11) bt Nicole Gibbs (USA) 6-4, 6-0
Casey Dellacqua (AUS x29) bt Karolina Pliskova (CZE) 6-3, 3-6, 6-4
Aleksandra Krunic (SRB) bt Petra Kvitova (CZE x3) 6-4, 6-4
Victoria Azarenka (BLR x16) bt Elena Vesnina (RUS) 6-1, 6-1
Ekaterina Makarova (RUS x17) bt Zarina Diyas (KAZ) 6-2, 6-4
Eugenie Bouchard (CAN x7) bt Barbora Zahlavova Strycova (CZE x30) 6-2, 6-7 (2/7), 6-4