Angelique Kerber of Germany plays a forehand in her third round match against Kristyna Pliskova of the Czech Republic on day five of the 2017 Australian Open at Melbourne Park on January 20, 2017 in Melbourne, Australia. World number one and reigning champion Angelique Kerber wasted no time in racing into the fourth round of the Australian Open with a 6-0 6-4 victory over Kristyna Pliskova on Rod Laver Arena on Friday.