The former French Open and Australian Open champion Li Na, the first Asian player to win a Grand Slam singles title, announced Friday morning in Beijing that she was retiring because of worsening of knee injuries that had plagued her throughout her career.

Li, 32, has not played since a third-round loss at Wimbledon in July. She withdrew from the United States Open in August, citing her knee injury, and announced her retirement in a letter posted on social media.

“The task of finally making a decision to hang up my racquet felt a lot more difficult than winning seven matches in a row in the Australian heat,” she wrote in the letter. “It took me several agonizing months to finally come to the decision that my chronic injuries will never again let me be the tennis player that I can be. Walking away from the sport, effective immediately, is the right decision for me and my family.”

Li had three surgeries on her right knee from 2008 to 2009 to alleviate problems caused by excess cartilage, and after her loss at Wimbledon she underwent a fourth surgery on her left knee.