On Tuesday, the Singles reigning champ lost her chance to defend her title at the 2016 Games, after getting bested in the third round!
Miz Williams lost to Ukraine's Elina Svitolina, who is ranked 20th in the world! Talk about an upset! The sports star was beaten by the blonde in two sets, 6-4 and 6-3.
This is the first time the tennis pro has left the Olympics without a single medal, taking home gold for Doubles in 2000, 2008, and 2012.
In 2012 she also took home the top honor for the Singles competition.
Unfortunately, Serena was apparently just off her A-game while in Rio.
[Image via AP Images.]