Watch: Petra Kvitova Stops Amanda Anisimova's Incredible Run at the Australian Open

Petra Kvitova became the first player to make it into the quarterfinals after taking down young American Amanda Anisimova.

MELBOURNE, Australia — Two-time Wimbledon champion Petra Kvitova is the first player into the Australian Open quarterfinals after beating 17-year-old American Amanda Anisimova 6-2, 6-1 to open play Sunday at Rod Laver Arena.

Kvitova, who had a WTA Tour-leading five tournament wins last year, extended her winning streak to nine matches after capturing the Sydney International title last week and her four wins at Melbourne Park this week. She hasn't made the quarterfinals here since 2012.

Anisimova, one of three American women playing fourth-round matches Sunday, beat seeded players in the second and third rounds. She was the youngest player to reach the Round of 16 here since 2006 and the youngest in any Grand Slam tournament since 2007.