* Both players struggle to hold serve
* Li survives late wobble serving for the match
* Li to face either Sharapova or Makarova
By Ian Ransom
MELBOURNE, Jan 22 (Reuters) - Winning Asia's first grand slam singles title became a burden that sapped the confidence out of Li Na, but the 30-year-old Chinese felt it come flooding back in reaching her third Australian Open semi-final on Tuesday.
The 2011 French Open champion overcame a bout of wayward serving to grind down fourth seed Agnieszka Radwanska 7-5 6-3 on a sun-drenched centre court, and will play either Maria Sharapova or Ekaterina Makarova for a place in the final.
Li had been lost in the grand slam wilderness since her Roland Garros triumph, failing to pass the fourth round of a major, but has embraced the old 'chemistry' at Melbourne Park, where she has made the semi-finals in three of the past four years.
"I really don't know what it is here," the sixth seed told reporters. "It seems whenever I come down here my results are always quite consistent, no big setbacks or anything.
"I'm not sure whether it's the winter training but it does seem like I'm just better at this tournament.
"With the Australian Open, it's like coming back and thinking, 'all my old friends are here'.
"It's the same in the locker room, too. Even if I haven't been here for two years, they'll help me look after things and they've even had me keep the same locker number."
A hard-hitter with an occasionally combustible temperament, Li's hopes of a maiden title at Melbourne Park were thwarted by both nerves and the eventual champions in 2010 and 2011.
She lost a tight two-set battle in the last four against Serena Williams in 2010 and crumbled under the pressure in the 2011 final against Kim Clijsters, after having moved into a winning position.
Li's new coach Carlos Rodriguez, the long-serving mentor of seven-times grand slam champion Justine Henin, had helped calm her mental demons and put her through a winter training regime she described as twice as rigorous as her previous camps.
"After three days (of it) I was really tired," she said. "I was calling my husband, saying, 'I really want to retire'. Only three days - how can I continue for three weeks or all the year?
"But I think he's good because you can see (the results) until now... It's not bad."
Despite losing to Radwanska in the semi-final of the warm-up tournament in Sydney earlier this month, Li told Reuters she would overturn the defeat and break the Pole's 13-match winning streak in the lead-up to the quarter-final.
Both players struggled to hold serve throughout, but Li had the best of the baseline duels on a sun-drenched centre court at Rod Laver Arena, despite bludgeoning 40 unforced errors along with her 32 winners.
Li held her serve at 6-5 to close out the first set, the first lost by Radwanska in her winning streak, but stumbled to fall behind 2-0 in the second.
"I was feeling my legs couldn't move... and I was feeling (like) totally dying," she said.
Li promptly reeled off the next five games to march to the brink of victory. She wobbled when serving for the match to concede two break points but saved them both and sealed the match when Radwanska floated a backhand long.
Not all was perfect in the win, however, with some serves flying high into the air off the frame of her racket and cannoning into the court before the net.
But Li was simply thrilled to get an extra half day's rest and let Sharapova and Makarova slug it out in the afternoon session.
"Now I can start now to enjoy my day. (Sharapova) has to fight," she quipped. (Editing by John O'Brien)