BEIJING — Ana Ivanovic has withdrawn from the China Open due to an upper respiratory infection, saying it seems like a fitting end to the season she's had.

Ivanovic said in a statement Saturday that it has been a very disappointing season.

The 21-year-old Serbian said her body was "quite fragile" following a combination of too much training and not enough recuperation.

Ivanovic, who won the French Open in 2008 and has reached two other Grand Slam finals, said she had to rework her serve after Wimbledon to accommodate a sore shoulder.

She was 24-13 in 2009, reaching only one final — losing to Vera Zvonareva at Indian Wells in March. She made the round of 16 at the French Open and Wimbledon, but lost in the first round at the U.S. Open.