The former world tennis number one Serena Williams has undergone surgery in Los Angeles to remove a blood clot from her lungs.
A representative of the tennis star says Williams underwent emergency surgery for a hematoma which resulted from treatment for a more critical situation - last week she suffered a pulmonary emobolism.
Williams has undergone two operations on her right foot since it was cut by glass at a restaurant. She has not played a top-level tennis match since capturing the Wimbledon title last July.
