"To see your career from the beginning to today was an honor," Williams wrote in a social media post saluting her fellow all-time great.

Federer penned an emotional tribute to his longtime rival ahead of Nadal's final tournament, writing that he "challenged [him] in ways no one else could."

"In the off-season, other players go to Maldives or Hawaii," she teased last week in Riyadh, "but I'll have too many commercials to shoot and no vacation."

The Italian's quest for a snapshot with Nadal began at the Paris Olympics, and is continuing this week before he says goodbye to the tour.

The Norwegian reflected on his retiring idol's impact and lessons taken from Jannik Sinner's lopsided ATP Finals win.