A clearly unwell Serena Williams and sister Venus pulled out of the Wimbledon women’s doubles on Tuesday as their tournament ended on a worrying note.
The WTA later announced that the reason for Serena's withdrawal was a "viral illness''.
In scenes that were uncomfortable to watch on Court One, Serena was plainly not herself and her vision looked to be the root of the trouble.
She served four consecutive double faults as the sisters surrendered the third game of their match against German Kristina Barrois and Swiss Stefanie Voegele.
At 3-0 behind the Williams sisters, who have won the Wimbledon doubles title five times, decided against taking the match any further.
In her service game, Serena was struggling to bounce the ball and keep it under any semblance of control, and the first two double faults at the beginning of her first service game highlighted the difficulties she was experiencing.
She was unable to clear the net at that point.
“Come on Serena” went the encouraging cheers from the crowd, but a third double followed and, although the 32-year-old had managed to get the ball into the opposite half of the court, her direction was all off.
Umpire Kader Nouni came down to the court to speak with the sisters, who carried on, but Serena’s fourth double fault in a row meant it was becoming a grim spectacle.
There was little option for the sisters to abandon the contest to allow Serena to seek assistance for the problem.
She had earlier called for the trainer before the match began after struggling through the warm-up.
The American pair, who have each won five Wimbledon titles individually, were knocked out of the singles in the third round last week.