Updated

Top seed and two-time defending champion Novak Djokovic advanced to the fourth round of the Australian Open on Friday.

Djokovic became the first man to the round of 16 with a 6-4, 6-3, 7-5 victory over Czech Radek Stepanek at Rod Laver Arena.

"Well, yes, definitely," Djokovic said when asked if this was his toughest match thus far. "I mean, I wasn't expecting an easy match coming into the third round and playing a seeded player; somebody that has a lot of experience playing on the tour."

The Serbian broke the 31st-seeded Stepanek once in each set and fired 37 winners.

Djokovic, who also won the title at Melbourne Park in 2008, is bidding to become the first three-peat champion in the Open Era at this Grand Slam event. He will next play either Switzerland's Stanislas Wawrinka or American Sam Querrey.

Other winners Friday were Djokovic's countryman, Janko Tipsarevic, Nicolas Almagro, Kei Nishikori and Kevin Anderson.

The eighth-seeded Tipsarevic rallied to beat 32nd-seeded Frenchman Julien Benneteau 3-6, 6-4, 2-6, 6-4, 6-3 and reach the fourth round Down Under for the first time. In doing so, he joined Djokovic as the second Serbian to reach the round of 16 at all four majors.

Up next for Tipsarevic, who improved to 17-8 in five-set matches, will be Almagro. The 10th-seeded Spaniard topped 24th-seeded Pole Jerzy Janowicz 7-6 (7-3), 7-6 (7-4), 6-1.

The 16th-seeded Nishikori advanced with a 7-6 (7-3), 6-2, 6-3 triumph over Russian Evgeny Donskoy. Nishikori became the first Japanese man to reach the quarterfinals at Melbourne Park in the Open Era last year.

Anderson, meanwhile, fought back to oust 22nd-seeded Spaniard Fernando Verdasco 4-6, 6-3, 4-6, 7-6 (7-4), 6-2. Anderson is the first South African man to reach the fourth round at a Grand Slam since Wayne Ferreira reached the 2003 Aussie Open semifinals.