Roger Federer has ended his superlative professional tennis career at age 41 with a loss in doubles alongside longtime rival Rafael Nadal at the Laver Cup.
The tennis queen gushed to one of the game's kings as they both depart.
"A few months ago we were joking about both being on crutches," Federer wrote.
The tennis star, who has won four gold medals at past Summer Olympics, did not want to disclose why she's chosen not to play at this year's games.
Williams fell way behind and could not put together a comeback against a much younger and less-experienced opponent.
The Serbian tennis player is the first man since 1948 to save championship points in the final and go on to win.
The 5-year-old royal also has another connection to Serena Williams.
The Swiss tennis champ is currently competing at Wimbledon.
The two tennis greats competed in the United States vs. Switzerland mixed doubles match at the Hopman cup.
The tennis legends will play a mixed doubles match on New Year's Day at the Hopman Cup in Australia.