HONG KONG - Nine minutes was all that Wang Qiang required to book her spot in the semifinals of the Prudential Hong Kong Tennis Open on Saturday, as she finished off a quarterfinal upset of top seed Elina Svitolina.

She needed much more than that to book a spot in her third WTA Singles final of the season, as the No.6 seed returned to Centre Court for a second time on Saturday and outlasted Garbiñe Muguruza for a spot in the final.

The Chinese No.1 rallied from 4-1 down in the final set to stun Muguruza in a nearly three-hour epic, 6-7(5), 6-4, 7-5.

"I felt nervous before the first match. I went on court a little bit shaky, but after two games, it was okay. I just went for it," Wang said at the close of her marathon day.

"I had nothing to lose against Muguruza, because she's a very good player. Both of us played very well today and I just tried to be more patient and use my chances."

Wang led the top seed in commanding fashion at 6-2, 5-2 when their quarterfinal was suspnded due to rain on Friday evening, and she held off the World No.5 upon resumption on Saturday afternoon.

Shewas in command on Friday, as she won the last four games of the first set and five of the first six of the second set to put herself in winning position against the top seed, who was looking to use this week in Hong Kong as a springboard for the WTA Finals in Singapore. 

Though Svitolina broke serve and held as the match resumed, winning consecutive games for the first time across two days, the World No.24 served out the match at her second opportunity and scored her first win against the Ukrainian in four career meetings.

Svitolina remains locked in a battle in the Porsche Race to Singapore, for one of the three remaining singles qualification places for the WTA Finals, with Karolina Pliskova, Kiki Bertens and Sloane Stephens.  

In the final four, Wang twice led by an early break in the first set, but was unable to keep her lead and had to battle from behind for the first time this week.

After again twice leading by a break in the second set, Wang came through the fire in stunning fashion to clinch it, coming from 0-40 down in the 10th game to eventually serve it out and send the match to a thrilling final set. 

"I just concentrated on court, point by point," Wang assessed. "I think I played good serves, good returns, and I did everything well today."

The result is the latest in a string of firsts for the 26-year-old this fall, as she reached her second WTA final in her past four tournaments.

The Svitolina win is Wang's first against a Top 5 player, and she scored another statement one against a two-time Grand Slam champion in Muguruza in the second semifinal, following the match between Dayana Yastremska and Zhang Shuai.

Despite Wang's marathon day, there will be no all-Chinese final in Hong Kong: the18-year-old Ukranian booked a spot in her first career WTA singles final with a 7-5, 6-4 victory. 

Read more: Yastremska blazes into maiden final in Hong Kong past Zhang

"I don't know a lot, but I know she's a young player and she plays really aggressive," Wang said. "I'll just try to do what I did today, tomorrow."