MELBOURNE, Australia (AP) Defending champions and top-ranked Serena Williams and Novak Djokovic had matches starting at the same time on nearby courts.
Six-time champion Serena Williams raced to a 6-1, 6-1 win in 45 minutes over 18-year-old Russian Daria Kasatkina on Rod Laver Arena. She will next play Margarita Gasparyan, who beat Yulia Putintseva 6-3, 6-4.
Djokovic took 25 minutes to win the first set against No. 28-seeded Andreas Seppi but needed almost an hour in the next two, saving two set points in the tiebreaker before winning 6-1, 7-5, 7-6 (6) on Margaret Court Arena. After making way for Williams on the main court, he noted it was his first match on Melbourne Park's No. 2 court since it was renovated to include a roof.
Djokovic has won five Australian titles and his victory maintained a streak of reaching at least the fourth round at every major since the 2009 French Open. He was also particularly wary of a third-rounder against Seppi, who beat four-time champion Federer at the same stage here last year.