Here's the 'untold story' of the legendary Serena-Federer selfie

For the very first time, legendary tennis stars Roger Federer and Serena Williams faced each other on the court at the Hopman Cup in Perth, Australia. 

Federer and her Swiss partner Belinda Bencic beat USA duo of Williams and Frances Tiafoe 4-2 4-3 (5-3) in a mixed-doubles contest to secure a 2-1 win for Switzerland in the round-robin tie.

Federer and Williams shared a good-natured interview afterward and then engaged in a selfie.

While the picture, which had a combined 81 Grand Slams, went viral on the social media and will surely go as one of the iconic pictures in the history of the sport.

However, it was later revealed that after the memorable interview and selfie, Serena took Federer's racket with her as a souvenir.

One of the yet untold stories of this pic last night is that @serenawilliams grabbed @rogerfederer racquet and took it home as a souvenir!@hopmancup @WilsonTennis pic.twitter.com/JJuCnRFDkk

— Todd Woodbridge (@toddwoodbridge) January 2, 2019

"It was so fun. This is super cool that we get to do it at such a pinnacle point of our careers," Williams said. 

"I was so excited, and literally it was the match of my career. Just playing someone so great, and someone you admire so much, and a match that actually means something." 

Federer and Williams have won 43 Grand Slam singles titles between them.

Defending champion Switzerland will qualify for Saturday's final if it beats Greece on Thursday. The United States, which lost to Greece on Monday, can't advance now.