Melbourne: Novak Djokovic remained on track to defend his Australian Open title with another dominant win as David Ferrer progressed and South African Kevin Anderson scored an upset Friday.

Two-time defending champion Djokovic was untroubled as he served his way into the last 16 with a straight-sets win over never-say-die Czech Radek Stepanek.

Out on Hisense Arena, Anderson eliminated 22nd seed Fernando Verdasco in five sets to earn a crack at Czech fifth seed Tomas Berdych, who beat Austrian Jurgen Melzer.

Spain’s fourth seed Ferrer also went through, ending the hopes of Cypriot Marcos Baghdatis 6-4, 6-2, 6-3 and next faces Japanese 16th seed Kei Nishikori.

World number one Djokovic, bidding for his fourth Australian crown, didn’t give Stepanek a look-in as he completed a 6-4, 6-3, 7-5 victory in an entertaining 2 hour 22 minutes on Rod Laver Arena.

Djokovic has yet to drop serve in three commanding victories at this year’s Open and has only had five break points against him in 43 service games.

The top seed will next face either American 20th seed Sam Querrey or Swiss 15th seed Stanislas Wawrinka in the round of 16 on Sunday.

“Radek loves the big stage. You saw how much fun he had. I also had a lot of fun playing. It was a very entertaining match,” he said.

“It was three close sets. I felt that I had much more chances on his serve than he had on my serve.”

Stepanek, the hero of the Czech Republic’s Davis Cup final triumph over Spain last November, kept charging in at Djokovic and ventured to the net 67 times to try to seize the initiative.

“I have respect for him because he’s a fighter, he’s a competitor, and somebody that is one of the rare players who comes to the net nowadays and mixes up his style of the game,” said Djokovic, whose ratio of 37 winners to 19 unforced errors underlined his form.

Anderson, who lost to Australian Bernard Tomic in last weekend’s Sydney International final, is bidding to emulate fellow South African Wayne Ferreira, who reached the semi-finals here in 2003.

He needed 3 hours 46 minutes before subduing the big-hitting Verdasco 4-6, 6-3, 4-6, 7-6 (7/4), 6-2 for his first win in three encounters with the Spaniard.

Elsewhere, Nishikori kept on the winning trail for a 7-6 (7/3), 6-2, 6-3 victory over Russian Evgeny Donskoy, while Swiss Stanislas Wawrinka beat American Sam Querrey in straight sets.

“Ferrer is playing well. He’s always tough to play. He gets every ball and is not easy to beat,” said Nishikori, looking ahead to his clash with the Spaniard.

Serbian eighth seed Janko Tipsarevic was taken to his second consecutive five-setter before overcoming Frenchman Julien Benneteau, and will next face Spanish 10th seed Nicolas Almagro in the last 16.

Almagro ended Polish 24th seed Jerzy Janowicz’s tournament, winning in three hard-fought sets.