The world number two was trailing her Czech opponent 4-3 in the opening set when she went over on her left ankle while serving and, after a brief medical time-out, decided she could not carry on.
The fifth-seeded Kvitova will now play Vera Zvonareva for a place in the final after the Russian easily overcame Maria Kirilenko 6-3 6-2 in the opening quarter-final.
Zvonareva, who won seven straight games in the middle of the match, has now won all six meetings with Kirilenko.
"Sometimes you have certain opponents who you have a tough time beating and some who you usually beat," Zvonareva told www.wtatennis.com.
"It just so happens I beat Maria every time but there's no secret, I'm just trying to play my game, trying to execute."
The second quarter-final also went to form, with third seed Victoria Azarenka continuing her mastery over Marion Bartoli with a 7-5 6-0 win.
Azarenka had won six of the pair's seven previous meetings - her only loss was through a retirement - but a close contest was in prospect when she dropped serve in the opening game.
However, she got back on serve and, from 4-5, went on to win nine straight games to complete a runaway victory.
"It was a battle in the first set but I stepped up my level in the second set and played a more aggressive style of game," Azarenko said.
Azarenka's semi-final opponent will be ninth seed Agnieszka Radwanska, of Poland, who beat Estonia's Kaia Kanepi 6-2 7-6.