While serving for the 2nd set in Dubai against against Caroline Wozniacki, Anna Chakvetadze collapsed on the court. She received a prolonged medical time out, resumed play, but then retired after one more point. It sounded scary when it happened and here is the video to prove it. I heard she was dealing with gastroenteritis, so she probably fainted due to dehydration, but I hope she is ok. The replay of it starts at the 35 sec mark.