Li Na of China returns a shot to Monica Niculescu of Romania in their womens singles quarterfinal of the WTA 2014 Shenzhen Open tennis tournament in Shenzhen city, south Chinas Guangdong province, 2 January 2014.[Photo/icpress.cn]

SHENZHEN, China - Chinese tennis icon Li Na, world No. 3, and her compatriot Peng Shuai entered the WTA Shenzhen Open singles' semifinals here on Thursday.

The 31-year-old Li, defending champion, will face eighth-seeded German Annika Beck, while fifth seed Peng will take on the unseeded Vania King from the United States, who knocked out World No. 7 Sara Errani in the Round of 16.

Li needed three sets to advance, defeating Romanian Monica Niculescu 7-5, 4-6, 6-4.

For the first eight games, Li played transcendent tennis. Rather than get drawn into the long grinding rallies favored by her slicing opponent, Li chose to strike early. The 31-year-old bore down with a less glamorous but more workmanship approach, breaking at 5-6 to take the first set.

Expecting the ball to come back every time from her agile opponent, Li stayed steady but didn't get a single look at a break; ultimately, she was the first to falter, giving away an error-ridden service game at 4-all.

Niculescu, serving for the set at 40-30, flattened a serve out wide, punished Li's return back into the same corner, and swung a forehand volley into the open deuce court.

A seesawing third set saw the players trade errors and breaks. Li held a 4-1 lead before hitting a threateningly rough patch. Serving for the match at 5-3, a series of groan-inducing errors gave yet another break back to Niculescu. Finally, Li managed to string together enough points on her opponent' s next service game to take the match.

"I had to work hard to find my rhythm today and play well against an opponent with such an unusual style of play," said Li, who had no complaints about such a tough match at this point in the season.

"I need to play these kinds of matches before the Australian Open; this way I can make the necessary adjustments and increase my belief in myself."

Peng Shuai spent just 66 minutes to dismantle her opponent, Jana Cepelova from Slovakia. Peng repeatedly closed to knock winning volleys and fearlessly changed direction to make winners with ease.

"I was not so nervous as I was in my other two matches so far. Although I'd never played Cepelova before, I played better than my other matches here. When my coach came out on the court, he just told me to keep doing what I was doing and that I didn't need to change much." said Peng.

Vania King upset Barbora Zahlavova Strycova 6-2, 6-4 to set up her semifinal match with Peng. King continued her winning rhythm against Errani the night before.

"I' m really excited," King said after the match. "Barbora didn't play her best today, but she's a great player and I'm looking forward to playing her many more times."

Annika Beck defeated Patricia Mayr-Achleitner after a 3-set battle. Achleitner seemed poised to disappear from the third set after an hour and a half of unrelenting angles from the 19-year old German, but managed to break at 0-5 to avoid the bagel.

"Thanks for those who are waiting here to support me even though it's very late," Beck said to the fans after the match. "I hope I get your support tomorrow against Li."