ZHUHAI, China - Top seed Kiki Bertems won a marathon opening semifinal at the Hengqin Life WTA Elite Trophy Zhuhai on Saturday, as she ended the title hopes of wildcard Zheng Saisai, 2-6, 6-3, 6-4, and reach her fifth final of the year.

After just missing out on qualifying for the WTA Finals for the second straight year, the top seed did not lose a set in round-robin play against Donna Vekic and Dayana Yastremska, but needed every minute of the two hours and 30 minutes on the match clock to defeat Zheng in their first meeting in over three years. 

From a set and a break down at 6-2, 2-1, Bertens won nine of the next 11 games to not only to tie the match at one set all, but build a 4-1 lead in the decider.

"I knew I had to do something else, because Saisai was putting so much balls back on the court and I just had not the energy to play those long rallies," Bertens said. 

"I was just mixing it up, trying to do some serve and volley, which was working pretty well, I was surprised with that. So I just kept on going for it.

"She gave me some mistakes also, so then I start believing that I could still turn this match around."

Buoyed by the support of the Chinese fans, however, Zheng battled back, and capped three straight games of her own with a titanic, 13-minute break of the Bertens serve to level the final set at 4-4. 

However, the World No.10 rounded into form down the stretch at just the right time, and captured the last two games of the final set, eventually sealing victory as Zheng's final forehand found the net. 

"I am happy how I played today, I fight until the end and I played pretty well at the beginning, first set," Zheng said in defeat. 

"Then in the second set she start to serve better, she wasn't serving that well in the first set. She gave me much more trouble when I returned, and I wasn't very focused on my serve, I was missing a couple like easy shots and I gave her my service game.

"In the third set I was down first, and then I really like worked hard to come back to 4-4 and I think I made a mistake, I was playing the new balls and I wasn't playing aggressive tactics.

"It's pretty close match and even though I didn't play the right moment the right way, but I'm happy I was fighting until the end."

Bertens won just one more point than Zheng over the course of the match, 88 to 87, and though each player broke serve five times in the match, the Dutchwoman's efficiency on her opportunities helped her come out on top.

She went 5-for-7 on her chances on Zheng's serve, while the World No.40 went 5-for-11, which included four unconverted break points down the stretch in the second set. 

Bertens will next face Aryna Sabalenka as she looks to cap her season with another title, as she looks to extend her head-to-head lead over the Belarusian to 5-1.

Bertens won the first four meetings between the two, including in St. Petersburg and Eastbourne this year, before Sabalenka recorded her first win against her at the Dongfeng Motor Wuhan Open.

"[I played] Aryna already a few times this year, but it's a final, so whoever is the best can win," Bertens said. 

"Before the match, it's just really like getting all the energy together and just trying to give it all, and that's what I've been doing all week.

"I think every day I'm surprising myself what's still in me, still the fighting spirit. I only can hope that I can have it one more time tomorrow. 

"We'll prepare as good as we can for tomorrow and hopefully I'll have one more final push and just give all the energy that's left in me."