Plenty of tennis fans were a bit uneased on Monday afternoon after Russian superstar Maria Sharapova claimed to reveal who she thinks is the game's greatest of all-time.
The 31-year-old had a fun rally with Rafael Nadal, the man she thinks stakes the claim as the world best in Tennis.
She took to Twitter to share her experience, posting a video of the rally with the caption: "Two minutes on court with the GOAT 🐐 @RafaelNadal #BucketList Was so nervous."
Nadal, the record holder for most titles won of an individual tournament (11) and 16-time Grand Slam winner is currently ranked at No.2 in the world.
He was recently overtaken at the top of the sport by rival Roger Federer.
The Swiss star claimed his 20th Grand Slam title in Australia earlier this year and the 36-year-old widely regarded as one of the best players to ever grace the sport.
So as you would expect, Sharapova's post - personally claiming Nadal to be the world's finest - did not go down so well with Federer's loyal followers.
Here's how Federer fans reacted:
It's the debate that will continue to rage on for eternity.
There might be slightly more to Sharapova's caption that meets the eye, though. After the Russian was banned for doping in 2016, Federer condemned her actions and called for a zero-tolerance policy to be taken in the future.
So perhaps, Sharapova has never truly forgiven him for those comments.
Meanwhile, Nadal initially called for Sharapova to be banned, as Sharapova later revealed, sent her a 'lovely' letter during her ordeal.
“He sent me a very lovely message showing me his support,” Sharapova said. “I have a big respect for him.”
Maybe that's what Federer has to do to get back in her good books too then?
In the meantime, however, both Nadal and Sharapova will be purely focused on getting themselves into shape ahead of the French Open, with Roland Garros just around the corner.