Petra Kvitova of the Czech Repubic celebrates after winning the Women's singles thrid round match against Caroline Wozniacki of Denmark Caroline Wozniacki of Denmark on day six at the China National Tennis Centre on October 5, 2017 in Beijing, China.
Czech Kvitova, ranked 18th in the world, faced an early break point but then dominated the opening set, and she stayed composed in the second.
The first nine games of the second set went with serve, but Wozniacki faltered when serving for the first time to stay in the match.
Petra Kvitova of the Czech Repubic is congratulated by Caroline Wozniacki of Denmark after winning the Women's singles thrid round match on day six at the China National Tennis Centre on October 5, 2017 in Beijing, China.
Image credit: Getty Images
And Kvitova clinched victory at the first opportunity on the floodlit main show court when her opponent floated the ball an inch over the baseline.
Kvitova goes on to face her compatriot Barbora Strycova, who saw off Australian Daria Gavrilova 6-0 6-4.
But third-ranked Elina Svitolina remains in the title hunt, the Ukrainian a 6-2 7-5 winner against Russian Elena Vesnina.
Next for Svitolina is an awkward-looking quarter-final against in-form French player Caroline Garcia, who won the title in Wuhan last week and is at her highest career ranking of 15th as a result.
Garcia was untroubled by her French compatriot Alize Cornet in the third round, coming through 6-2 6-1.