The 21-year-old rising Chinese star is fresh off a statement summer during which she lifted a maiden WTA trophy and reached a first Grand Slam quarter-final at the US Open.

Up next is a rematch with Jasmine Paolini, who lost to the world number 24 in the Palermo final in July.

"It's been a long time I didn't arrive to the semi-finals at a WTA 500 tournament so this is a big step for me again," said Zheng, who won Asian Games gold this month.

"It was a tough match against Paolini in Palermo, I think she's really difficult to beat. She's a good fighter."

Facing Kalinina for the first time at tour level and third time overall, Zheng dropped just four points behind her first serve en route to grabbing the 41-minute opening set.

A marathon third game in the second set saw Kalinina save six break points but she faltered on the seventh to hand Zheng a 2-1 advantage.

That was all the home favourite needed to cruise to victory.

Paolini defeated Germany's Laura Siegemund 6-0, 7-5 in one hour and 44 minutes to reach her second WTA semi-final of the year.

"I'm feeling good, I'm playing a good level and I'm very happy to be in the semi-finals," said Paolini, who knocked out sixth seed Caroline Garcia in the previous round and is competing at her highest ranking of 31.

Former French Open champion Barbora Krejcikova spent just 45 minutes on court before securing passage to the semi-finals when Lesia Tsurenko retired after dropping the first set 6-3.

The Ukrainian qualifier was suffering a back problem.

Krejcikova will square off with eighth seed Daria Kasatkina for a place in the Zhengzhou final.

Kasatkina was handed a walkover into the last four after the withdrawal of her Tunisian opponent Ons Jabeur, who pulled out of the tournament citing a knee injury.

Jabeur will not be competing at her home tournament in Monastir and is in a race to be fit for the WTA Finals in Cancun at the end of this month.