The No. 9 seed Victoria Azarenka's US Open took an unfortunate and dramatic turn when the Belarusian collapsed and was helped off the court in a wheelchair during her second round match against Gisela Dulko on Wednesday. She was losing 1:5 when she felt down and could not continue playing.

USOpen Tournament Referee Brian Earley said that it was not due to heat, later Zarneka stated the following:” I fell while running a sprint. I fell forward and hit my arm and head. I was checked by the medical team before I went on court and they were courtside for monitoring. I felt worse as the match went on, having a headache and feeling dizzy. I also started having trouble seeing and felt weak before I fell. I was taken to the hospital for some medical tests and have been diagnosed with a mild concussion."

You can watch this match here http://www.youtube.com/watch?v=ap9CgKY3Ul4.