(CNN) -- In what was a bizarre, disturbing scene at Wimbledon, Serena Williams withdrew from her doubles match with sister Venus Williams on Tuesday due to a viral illness.
"I thought I could rally this morning, because I really wanted to compete, but this bug just got the best of me," Serena Williams said in a written statement.
The Women's Tennis Association said in a release that Serena Williams, a five-time Wimbledon champion at doubles, had a viral illness.
During warmups Tuesday, Williams stumbled around the court and looked disoriented. She had trouble catching balls thrown to her.
Following the warmup, a tournament doctor examined her on the bench, at one point taking her blood pressure. During the 11-minute break, Williams put her head in her hands and appeared to cry.
She decided to try to play, but it was tough to watch. At one point, Williams missed on a shot.
When it was her turn to serve, it was an entire game of uncharacteristically wild double faults.
At that point, the Williams sisters retired from the match, down 3-0.
"Unfortunately Serena has been feeling unwell for the past few days and she just couldn't play to her potential today," Venus Williams said. "I'm really proud of her for trying."
Tennis analyst Pam Shriver tweeted that no one she talked to could remember someone so clearly out of it on the court.
Germany's Kristina Barrois and Stefanie Voegele of Switzerland advanced to the third round with the default.
Both Williams sisters have been eliminated from singles' competition.