The defending champion has had a largely disappointing season but thrashed Fed Cup team-mate Klara Zakopalova 6-0 6-1 in just 50 minutes.
Kvitova had struggled through her previous matches so was delighted to be off court so quickly three days before the start of the US Open.
The former Wimbledon winner said on www.wtatennis.com: "It was nice to finally have a two-setter.
"I was asked in a press conference this week if I prefer shorter matches. And I said, 'Of course, I prefer shorter matches but it's not always up to me'."
In the final Kvitova will meet Romania's Simona Halep, who knocked out fourth seed Caroline Wozniacki 6-2 7-5.
Halep, who will play Britain's Heather Watson in the first round in New York, has been in brilliant form this summer and has won three of her last six tournaments.
She said: "I'm really, really happy that I won this match because I was nervous before the match - she's a top player.
"I have a lot of confidence right now. This has been a good period for me. I've been playing really well and feeling the game really well, and I'm enjoying myself on the court much more than I was before."