Li Na's superior strength and fitness told as she reached the Australian Open semi-finals on Tuesday after a pre-season training regime that was so tough, she considered quitting the sport.
Li reached her first Grand Slam semi-final since winning the 2011 French Open with a 7-5, 6-3 win against Agnieszka Radwanska, the world number four who had been unbeaten this year.
It was a powerful performance by the Chinese sixth seed, whose physical prowess allowed her to dominate diminutive Pole Radwanska after an erratic first set.
Li was formerly coached by her husband, Jiang Shan, but Carlos Rodriguez, Justine Henin's former handler, took the reins last year.
But Li, 30, said she was so exhausted after three days of off-season training in December that she told Jiang her career could be over.
"We train every day for five, six hours, but not only playing tennis," Li said. "Tennis was like maybe two, three hours. Fitness was for two or three hours as well.
"First time I was training with him, I was so excited, but after three days, I was dying. My husband didn't come with me to Beijing.
"I called him and said, 'Carlos is crazy'. He was like, 'Why?' I described the program to him. He was like, 'Don't joke'. I said, 'Hey, listen, I'm not making a joke."
She added: "After three days I was really tired. I called my husband and said, 'I really want to retire'. It was only three days. How could I continue for three weeks or all the year?"
However, the work has paid off with Li just one match away from her third Grand Slam final, and second in Australia. She will play either world number two Maria Sharapova or Ekaterina Makarova on Thursday.
Li also conceded her off-court life was less complicated now her husband was no longer her coach, and said she was now happier than during previous times in her career.
"We always had good communication but coach and husband is a tough balance," she said. "He was doing a very good job, but it was very tough.
"Because sometimes if he said we should do something, I was feeling like, I'm tired. You're my husband. Why should you be training me so hard?
"I forgot he was coach as well. That's sometimes why we have to fight, we have the shouting.
"The funny thing is, two years ago, in China, someone said I was divorced. They thought because we were always shouting, maybe we divorced. They ask me, 'Li Na, we hear you are divorced?'"
She added that she felt comfortable playing at the Australian Open, where she reached her first Grand Slam final in 2011 and has now reached the semi-finals three times.
"It feels like a home tournament for me," she said.