China's Li Na serves during the quarterfinal match of women's singles against Andrea Petkovic of Germany at the Australian Open tennis tournament in Melbourne, Australia, Jan. 25, 2011. (Xinhua/Meng Yongmin)

Australian Open semifinalist Li Na says a two-year break from tennis in her early 20s when she studied journalism at university helped persuade her to give the sport a second go.

The 28-year-old Li charged into her second consecutive semifinal at Melbourne Park on Tuesday when she beat Germany's Andrea Petkovic 6-2, 6-4 on Rod Laver Arena.

The world No 11 will move back into the top 10 following the win and has a good chance of going on and creating history by becoming the first Chinese player to win a Grand Slam singles title.

It is all a far cry from 2001 when she was languishing in the rankings and decided to quit tennis to study at university in her home city of Wuhan.

"I went to university from 2002 to 2004," she said. "There were two years I didn't play tennis because I was thinking about how I only had a lower ranking, always like around 120, and I never had a chance to play a big tournament, I was always playing challengers.

"So I felt like I should give up because I couldn't find anything positive, so I went to university for two years."

But she said that during that time she had always wanted to get back on the court.

"After two years, I was feeling like, okay, I'm grown up, I should stand up and try my best, so in 2004 I tried to come back," Li said.

When she came back in 2004 she was a different player, winning China's first ever WTA title in Guangzhou and reaching the top 100 for the first time.

She cracked the top 30 in 2006 and the top 20 in 2009 before her breakthrough in 2010, when she reached the semifinals in Melbourne and the Wimbledon quarterfinals, making the top 10 for the first time.

Li is undefeated in 2011, beating Kim Clijsters in the final of the Sydney International, and she showed great touch and calmness to defuse Petkovic's powerful game on Tuesday.

She must now be considered a genuine contender to secure China's maiden Grand Slam singles title, after Zheng Jie and Yan Zi teamed to win the Australian Open and Wimbledon women's doubles in 2006.

"I played really well in Sydney and I hope I can do better here this year. I don't want to lose in the semis again," she said.