Melbourne: Wimbledon champion Petra Kvitova continued to make amends for an upset first-round loss last year at the Australian Open with a 6-2, 6-4 second-round win on Thursday over Mona Barthel.
Fourth-seeded Kvitova held her serve in the sixth game of the second set through nine deuces, then broke Barthel in the ninth game, helped when the German player served a double-fault on break point.
Kvitova, who won her second Wimbledon title last July, next plays American Madison Keys, who beat No. 29 Casey Dellacqua in three sets.
Last year, Thailand's Luksika Kumkhum, playing just her second Grand Slam tournament, upset Kvitova in the first round at Melbourne Park.