Kvitova showed no mercy against her Czech Fed Cup team mate, racing to victory in just 50 minutes, to remain on course to defend the title she won in Connecticut last year.
Kvitova's opponent in Saturday's final will be Romania's Simona Halep, who upset four-times New Haven Open winner Caroline Wozniacki of Denmark 6-2 7-5.
"I don't think I've played Simona before," said Kvitova. "I know that she's a very good mover."
For Kvitova, who won Wimbledon in 2011, Saturday's final provides her with the chance to claim her 11th career title and her second this year.
The 23-year-old had struggled in her previous matches so was relieved to get through quickly against her compatriot.
"It was nice to finally have a two-setter," she said.
"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!'"
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- Simona Halep