China's tennis chief has blamed Li Na's failure to build on her stunning 2011 French Open victory on a lack of mental strength following her rigid state-organised training, according to a domestic report.
Sun Jinfang said the world number eight, who crashed out of the US Open in the third round on Friday, was prone to breaking down on court, blaming this on the fact she had focused purely on sport from an early age.
"We have seen for a long time that Li Na can suddenly collapse. Why is this? Because athletes like her have not received a good education," China's official Xinhua news agency quoted Sun as saying in a televised interview.
"Li Na has made the choice to concentrate on tennis from a very early age, but a very important piece of her education has been missing.
"Consequently, she has not developed enough mentally. There are lots of things that she cannot work out for herself.
"She knows when she is on the verge of a (mental) collapse... but she does not know how to react to this situation."
China's high-pressure state sports school system, which sees young children undergoing rigorous training for up to seven hours a day, has been criticized for not providing a fully rounded education.
Li opted out of the national state sports system in 2008 under a pilot scheme that allows tennis players to set up their own training team and keep most of their winnings.
After her decision to break away, Li enjoyed a run of good form that culminated in her becoming the first Chinese tennis player to win a Grand Slam singles title last year.
But her 2hr, 25min defeat to British giant-killer Laura Robson in New York last week represented the first time since 2008 that she had not reached at least the quarter-finals at any Grand Slam event during a season.
Sun previously criticized China's sports system for holding back athletes following Li's French Open victory.
Li has also called on sports authorities to give other athletes the right to pursue their careers without strict government controls.