With the loss, Kvitova extended her losing streak against Barty in their head-to-head to three matches and her drought at the WTA finals to eight. It is also the Australian's first-ever straight sets win against Kvitova, reports Xinhua news agency.
The stakes were much higher for the Czech going into the meeting. She needed a straight sets win to have a certain chance of advancement, while Barty had the breathing room to drop a set and could even have advanced in a three-set loss depending on the result of the game-percentage tiebreaker after the Bertens-Bencic red group meeting.
Each player held their opponent to 15 on their opening service games, but Kvitova was made to really sweat on her second, saving a double break point but managing to just hold on with an ace along the way.
Kvitova turned up the heat a bit on Barty's service at 2-all, but Barty managed to outwit her backhand with an all-court push. Barty went up a break off a passing shot that forced a netted return from Kvitova.
Although still trailing, Kvitova kept up the pressure on Barty, but could never manage to overcome her rough start. Barty saved a triple break point to hold and go 4-2. Kvitova would almost have the chance to break back after Barty double-faulted at deuce serving at 5-2, but the Australian kept it tight and managed to stave off her fourth break point of the opener.
Barty went on to serve out the 50-minute opening set with a hold to 15 on her last service game. She fired three aces off 64 per cent first service shooting overall in the opener. Kvitova coughed up 14 unforced errors, twice that of her opponent, blunting the effect of her 13 winners to 9 for Barty.
Kvitova had trouble out of the gate in the second set, dropping a 30-0 lead off two dropshot unforced errors to hand Barty a triple break point on a golden platter.
Kvitova was having trouble closing out points throughout the game and struggled to keep up with Barty's fluid movement around the court.
Although Kvitova hold twice to at least get on the board in the second set, as was the case in the opener, her early deficit was just too steep for the Czech to overcome. Barty served for the set at 5-2, and although Kvitova fought to 40-30, she was unable to upset the Australian's march into the semis.
Kvitova only managed to win 41 per cent of her first service points in the second set, notching 11 unforced errors to only 7 winners on the way to dropping the match in 90 minutes.
( With inputs from IANS )