Barty, who is a 2017 finalist at this event, forehand did the damage while her serve was also solid and finished with more winners and less unforced errors than Kerber.
Halep, who injured herself in training earlier this week, offered some resistance in the second set after a bad start to the match, but could not prevent an early exit in her first tournament since the US Open.
It was one-way traffic in the second as Barty quickly moved to a 5-0 lead before closing out the match on serve.
Kvitova battled valiantly in the final game of the match, but after saving four match points she finally succumbed - leaving Pavlyuchenkova to progress to a quarter-final tie with Ashleigh Barty, who had knocked out Kerber earlier in the day.
In-form Barty is now ranked 17th in the world, and a strong finish in Wuhan - a WTA Premier 5 tournament with 900 points for the victor - could help her inch up the rankings before the end of the season.
Farhan Akhtar to Priyanka Chopra, young Bollywood backs Tanushree Dutta
At that time I didn't even know everything that had happened, and so I wondered why he would say something like that. She is not cooperating.' Then she came out and went back to the set and we thought now the shooting would begin".
Arsenal boss Unai Emery avoids Aaron Ramsey contract questions amid uncertain future
My focus is always on the team. 'My focus is prepare with the players, only thinking on the match tomorrow. This puts the two Serie A clubs in direct competition with each other to secure his signature.
Panthers Sign Eric Reid Despite Collusion Grievance Against NFL
Coach Kyle Shanahan confirmed Thursday that the 49ers seriously pursued the possibility of re-signing veteran safety Eric Reid . The NFL Players Association, which supported Reid's grievance against the league, sent its congratulations to Reid.
Barty was beaten by Garcia in the Wuhan final previous year and the Australian stayed in contention to go one better.
"She's always very hard to play against".
"From the beginning of the season, the goal has been top 20 for this year", she said.
In the second round of the doubles, Taiwan's Hsieh Su-wei and Bethanie Mattek-Sands of the United States fell to a 7-6 (7/1), 2-6, 10-7 defeat to Czech second seeds Andrea Sestini Hlavackova and Barbora Strycova in 1 hour, 40 minutes.
Local hope Wang Qiang eased past qualifier Monica Puig 6-3 6-1 to reach the last four. "Certainly would have been nicer to get it done in straights today", Barty said.
Puig had come from a bagel set down to defeat the Australian Open champion 0-6 6-4 6-4 in the second round at the Miami Open in March and the 24-year-old repeated the dose with a forehand victor to set up a clash against home favourite Wang Qiang, who defeated Daria Gavrilova in straight sets, in an all-unseeded battle.