Serena Williams makes short work of Daria Kasatkina

The No. 1 seeds in both the men's and women's singles won third-round matches without the loss of a set at the Australian Open on Friday in Melbourne.

Serena Williams, a six-time champion in this event, cruised past 18-year-old Daria Kasatkina 6-1, 6-1 in just 44 minutes, the shortest match at the Australian Open so far.

Novak Djokovic, the top-ranked male player and a five-time Australian Open champ, had to work harder but prevailed 6-1, 7-5, 7-6 (6) victory over Andreas Seppi, who let two set points get away in the third set.

Williams was so dominant that there was little talk about afterward other than her on-court look: a two-piece yellow outfit with a crop top and pleated skirt.

"It's built for speed," Williams said. "I live in a crop top, sleep in crop tops. I'm often never seen without one. So I thought it would be really fun to play in one."

The 34-year-old Williams seems to be playing some of her best tennis despite concerns about her sore knees and her four-month layoff.

Williams will play 58th-ranked Margarita Gasparyan in the fourth round.

Because Williams occupied the main stadium court, Djokovic was relegated to Margaret Court Arena for the first time in nine years in his match.

Djokovic won the first set against Seppi in just 25 minutes, but he had to struggle a bit in the next two sets to finish off the two-hour, 21-minute match.

Djokovic got the service break he needed in the second set on a 32-shot rally to give him a 6-5 lead.

Djokovic never did break serve in the third set, and Seppi had two set points in the tiebreaker. But Seppi, who eliminated Roger Federer in the third round of the Australian Open last year, was unable to finish it off, and Djokovic advanced.

The match could have gone either way," Djokovic said. "I didn't think it was going to be as easy after the first set. He was going to step up his game and make it more competitive."

Djokovic next plays Gilles Simon, a 6-3, 6-2, 6-1 winner over Federico Delbonis.

In a later match, 2014 U.S. Open champion and 12th-seeded Marin Cilic lost 6-4, 7-6 (5), 7-5 to Roberto Bautista Agut of Spain.

The 24th-seeded Bautista Agut will now face sixth-seeded Tomas Berdych, who beat temperamental Australian Nick Kyrgios 6-3, 6-4, 1-6, 6-4 in the third round.