American tennis star Amanda Anisimova was enjoying a beverage during her Round of 32 match in the Cincinnati Open on Monday night. A world-class athlete replenishing themselves during competition is, of course, normal behavior, but at first glance it appeared that Anisimova was consuming a drink that has the opposite effect of rehydration.

After dropping the first game of the final set in her match against Alex Eala, the Tennis Channel broadcast showed viewers at home a clip of Anisimova taking a few sips of a mystery beverage from a plastic cup she took out from underneath a towel on her bench during the second set.

The fact that the mysterious beverage was being drunk out of a plastic cup, one that Anisimova was trying her best to hide, made fans understandably assume that she was sipping on a cold beer.

It wasn't just fans who shared the thought, either, as broadcasters Brett Haber and Lindsay Davenport questioned what exactly the beverage was.

"Could be apple cider, Brett," Davenport said.

"I mean, I would never suggest that a player was drinking a beer in the middle of a match, but that’s certainly what it looked like," Haber remarked.

Coupled with the fact that it was unclear what the beverage was and that players are prohibited from consuming alcohol during a match, Haber was sure to cover his tracks.

"It could be non-alcoholic. It could be cider. It could be anything. We don’t know," Haber said.

Anisimova, 24, ultimately cruised in the third and final set, winning 6-2 to advance to the Round of 16. With fans convinced that she was drinking a beer during the match that she went on to win, it only added to the fun on social media.

"I don’t know if I have ever seen anything more nails than Amanda Anisimova just drilling a beer mid game and then winning the match," a fan wrote on X. "Beers have never been more back."

Some fans guessed that it was Red Bull, or a similar-looking energy drink, that was in Anisimova's plastic cup, and those fans were correct, according to Haber.

"We can confirm via one of our courtside camera operators that Anisimova asked for and was delivered a Red Bull. That is the mystery bevvie," he explained on the broadcast.

Sipping on a Red Bull mid-match is far less intriguing than sipping on a cold beer, but the moment still made for some fun on social media and across the tennis world.

Anisimova will take on Linda Noskova on Wednesday.