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The eighth-seeded Czech will meet the winner of US Open champion Naomi Osaka and seventh seeded compatriot Karolina Pliskova as she bids for her first Grand Slam triumph since claiming the second of her Wimbledon titles in 2014.
The match at Rod Laver Arena was riven with tension, with a delay to close the roof during the first set due to the stifling conditions and a malfunction of the net cord sensor at the start of the second that left server Collins fuming.
Kvitova capitalised on the American's distraction to break her three times in succession on the way to an emphatic victory that made her the first Czech woman to reach the Melbourne final since Jana Novotna lost the 1991 decider to Monica Seles.