The Scottish First Minister picked up a racquet while on a visit to the Dennistoun district of the city, but faced perhaps stiffer competition than she expected in the form of Anne McLaughlin.
Serving to start the game, the former SNP MP struck the tennis ball hard and fast, swinging it straight into the back of the leader of her party's head - causing hands to be clapped to faces in shock and amusement by the crowd gathered to watch.
Sharing a video of the moment, Ms Sturgeon tweeted: "Great time in Dennistoun today - until the moment @AnneMcLaughlin whacked me on the head with a tennis ball!
Ms McLaughlin responded to the video on Twitter, jokingly replying: "I play to win these days. And I did."