Keys upsets Wimbledon champion Petra Kvitova at Australian Open

Melbourne: Wimbledon champion Petra Kvitova is out of the Australian Open, beaten 6-4, 7-5 by 19-year-old American Madison Keys.

At 5-5 in the final set, Keys, coached by three-time Grand Slam singles champion Lindsay Davenport, got the pivotal break of serve. She held in the next game, screaming with delight when Kvitova netted a backhand on match point.

Keys will play another American, Madison Brengle, in the round of 16, guaranteeing at least one U.S. player in the quarterfinals. Serena and Venus Williams also remain in the singles draw, also in the same half as Brengle and Keys.

Last year, Thailand's Luksika Kumkhum, playing just her second Grand Slam tournament, upset Kvitova in the first round at Melbourne Park.