Caroline Wozniacki resisted a sizzling baseline display from China's Zheng Jie to reach the semi-finals of the Indian Wells WTA tournament with a hard-fought 6-4, 4-6, 6-1 victory on Wednesday.
The second-seeded Dane, who had been beaten by Zheng in their two previous meetings, broke her opponent three times in the final set to win the match in two hours 18 minutes.
Wozniacki, at 19 the youngest player left in the tournament, let out a shriek of delight after 18th-seeded Zheng pushed a backhand wide to end a fluctuating encounter of high quality.
"It was a long match and it was really tough," the Dane told reporters.
"She played really well and got a lot of balls back that I thought I had won already.
"Both of us played really aggressively trying to make the other one run because the one who opened up the point won the point most of the time. I'm really pleased about my game today," she added.
Wozniacki will next meet her good friend Agnieszka Radwanska of Poland, who breezed into the last four with a 6-4, 6-3 victory over fourth-seeded Russian Elena Dementieva.
Radwanska, who has yet to drop a set at Indian Wells, broke her opponent twice in each set to win the match in one hour 31 minutes.
"I'm very happy I am in this condition, always playing two sets," a smiling Radwanska said after sealing victory when Dementieva hit a backhand service return long.
"It's always better to win in two sets but it's hard, especially here," she added.
The Pole, a winner of four WTA titles, was delighted to extend her winning record against Dementieva to 4-2 on a sunny afternoon in the California desert.
"We've played on different surfaces but Elena is always very tough," Radwanska said after converting six of her eight break point opportunities.
"If I win the match, I'm just a couple of points better. It's not like 6-1 and 6-1. If it's an important moment, I think I'm just little bit better."
Dementieva, a losing finalist here to compatriot Maria Sharapova in 2006, was frustrated with her display on the stadium court at the Indian Wells Tennis Garden.
"It was a perfect day to play tennis, and this year it's not windy," the 28-year-old said. "It's beautiful weather.
"I just didn't play the way I should to beat her. I was actually playing her game the way she feels pretty comfortable with the long rallies."