Something really weird was going on with Serena Williams at Wimbledon today. Two games into her and her sister's doubles match against Kristina Barrois and Stefanie Vogele, Serena suddenly became very disoriented and physically unable to hold onto the ball or hit a serve. It was scary to watch.

After feebly sending multiple serves into the net, Serena and Venus retired from the match, walking off the court hand in hand. It appears that whatever went wrong with Serena started happening before the match even began, and there was some question as to whether it would start at all.

We'll update when we know more.

Update:

[ESPN]