The Dane recovered from an injury scare, where she needed taping to her left knee early in the second set, and showcased her athleticism in a dominant third set to outlast Kvitova.
Elina Svitolina cut a disconsolate figure a year ago as her WTA Finals debut petered out with a group stage exit after some poor performances in the Singapore Indoor Stadium. Analyzing her win over Kvitova, the Dane said: I think I played somewhat similarly the whole match through, and I think in the second set I didn't think I played bad.
"I always believe in myself and when I'm out on the court I believe I'm going to win".
"It was a really challenging opening match, and this one, as well, so I'm very happy that I could handle those two, and I still have my next match very, very tough and, you know, I'm looking forward to it". "I'm exhausted right now. more exhausted than after my first match, definitely", she said.
Wozniacki, who became the first Danish woman to win a Grand Slam title at this year's Australian Open, is now 1-1, while Kvitova is 0-2. "So, I just stayed focused and got a lot of balls back".
The Ukrainian sixth seed edged a tight first set, but was blown away in the second beofre clinching a 6-3, 2-6, 6-3 win over Czech seventh seed Pliskova.
That danger was quelled and, with Kvitova serving to stay in the set, Wozniacki saw another set point go missing before the third time proved a charm when the Czech put a forehand into the net.
The Ukrainian has been in stellar form in Singapore in a determined effort to make amends for an early exit in her WTA Finals debut previous year.
But Svitolina rediscovered her irresistible form from the first set and forced the Czech into errors. It took the Ukrainian three sets to beat the opponent (6:3, 2:6, 6:3).
Even though she lost, Pliskova remains in the hunt to qualify for a second successive WTA Finals semi-final. In the ninth game Svitolina again showed character - feeding on the set, Elina played two break-point and took the match.