Before Tuesday's second round doubles match at Wimbledon, Serena Williams was struggling to hit balls, seemed disoriented, and even started crying.
And then things got even worse for her during the match.
Which caused a lot of commotion on Twitter:
Serena Williams is playing doubles with Venus right now and something is very very wrong. Just hit four straight BAD double faults.
This is the most bizarre thing I’ve ever seen in a tennis match.
Watching Serena Williams just now was very unnerving...looked like she had a stroke or something. Sure hope she's alright.
This is insane. Serena Williams can’t even get a serve to the net. Stop this thing.
After some disturbingly bad and bizarre play, which caused one of the commentators to declare that she's "never seen anything like this before," the match was ended on a forfeit from Serena and Venus.
Although no one is totally sure what happened, on Saturday, after losing to Alize Cornet, Serena Williams said in a post-game interview that "I suck right now at doubles. I told Venus the other day I don't even want to play because I'm so bad right now. She should get a new partner."
Update — July 1, 12:55 p.m. ET: According to SI Tennis, the official reason for Serena Williams' exit was "viral illness."