Holder Aryna Sabalenka fought back from a first-set stumble to beat Coco Gauff 1-6 6-4 6-4 in the Wuhan Open semi-finals as double faults proved to be the American's undoing on Saturday.

The 20-year-old Gauff, who has made some grip changes with new coach Matt Daly, made 21 double faults as top seed Sabalenka, who struggled against the world number four's power earlier in the match, swung the momentum in her favour.

"Couple of mistakes from her and I thought maybe I still have (a) chance in this match ... it was a very important win," Sabalenka said in the post-match interview after reaching the Wuhan Open final for the third time in a row.

The Belarusian will face the winner of an all-Chinese semi-final later on Saturday between fifth seed Zheng Qinwen, who won Olympic gold in Paris this year, and Wang Xinyu.

Three-times Grand Slam winner Sabalenka found it hard to control her returns when Gauff got the first serve right, repeatedly overshooting the lines or finding the net.

Former U.S. Open champion Gauff broke twice to build a 5-0 lead, with Sabalenka holding only once in the first set, which Gauff won with a forehand that left the world number two rooted to the spot across the court.

Sabalenka started the second set on an aggressive note, summoning the best of her strength on the shots. She finally found success as Gauff struggled to hold her own serve.

Gauff's double faults coupled with slower, nervous second serves allowed Sabalenka to pressure her with power shots as the Belarusian won four games in a row to win the second set 6-4.

Sabalenka's winning momentum continued in the third set as she went 4-1 up before Gauff got her first break in the set to make it 4-4. However, Sabalenka took control again, getting another break to win the match.

"I'm really happy to be in the final. One more to go and I will do everything I can to win this beautiful trophy for the third time," Sabalenka said. "It will be a great match."