Roundup: Australian Open enters business end

The Australian Open has entered the business end for the world's best after round three concluded on Saturday.

American Serena Williams proved she's the lady to beat down under, defeating compatriot Nicole Gibbs 6-1, 6-3 in just over one hour, moving on to round four and the Australian Open second week after a tough start.

"I feel like I have been able to do pretty good" in the first week, Williams told reporters.

"I have been doing the things I have been doing in practice, and hopefully I can build up on this."

Williams will take on Barbora Strycova in round four after the Czech world No. 16 defeated France's Caroline Garcia 6-2, 7-5 on Saturday.

World No. 6 Slovakian Dominika Cibulkova however won't be hanging around for the second week after Russian star Ekaterina Makarova went through 2-6, 7-6 (3) 3-6 in just under three hours.

Spaniard Rafael Nadal continued his comeback, coming from two sets to one down to defeat the young German Alexander Zverev 6-4, 3-6, 7-6 (5), 6-3, 6-2. The outstanding play of the youngsters has been a theme of this year's open, with some of Australia's up and coming talent making into the later rounds.

"(It was) a tough match," Nadal said of the four hour marathon against the 19-year-old world No. 24.

World No. 1 Andy Murray will take on Germany's Mischa Zverev in their round four clash on Saturday, the first time the two have met since they met in Munich in 2015. Murray defeated Zverev 6-2, 6-2.

But hometown hero Roger Federer will need the crowed on his side as he takes on Japan's Kei Nishikori in the first night match on center court. Federer has defeated Nishikori on four of the six occasions they have met, however the Swiss ace is returning from injury while Nishikori is fighting fit.

Federer said it will be an exciting match for him coming off a straight sets win over Tomas Berdych where he was surprised by how well he played given Nishikori has played better and more tennis than him over the past few months.

"I'm a big fan of his game," Federer told reporters after his 6-2, 6-4, 6-4 win, adding he' s got one of the best backhands in the game, while loving how he can "crush it down the line or cross court" and his "wonderful second serve returns."

"He's fast on his legs, strong in his mind, I know how tough he is as the match goes along," Federer said.

"He finds his range and his rhythm, he's tough to stop."

Women's top seed Angelique Kerber will face American Coco Vandeweghe in Sunday' s final in showdown. While their world rankings are far apart -- Vandeweghe is currently ranked 35 in the world -- and Kerber has won all their meetings, it's destined to be a sure test.

"Coco is a tough opponent," Kerber told reporters after her round three win against Kristyna Pliskova.

"I know she is serving good (at this tournament).

"I have to move good, being ready, bring a lot of balls back, but also being aggressive, as well, like I can play." Endit