Linz, Austria -- (Sports Network) - Two-time Grand Slam champion Mary Pierce suffered a ruptured anterior cruciate ligament in her left knee on Thursday and will need to undergo surgery.

Pierce was leading Russian Vera Zvonareva 6-4, 6-6 when she fell behind the baseline during their second-round match at the Generali Ladies Linz tennis event. The French star left the court on a stretcher at Intersport Arena.

The 31-year-old Pierce, last year's runner-up at the French and U.S. Opens, appeared in only eight tournaments this season due to injuries.