Melbourne, Australia (SportsNetwork.com) - Former champions Novak Djokovic and Stan Wawrinka continued to plow through the top half of the draw at the Australian Open with third-round wins Saturday.

The top-seeded Djokovic had his first minor test of the fortnight with a first-set tiebreaker, then rolled from there to capture a 7-6 (10-8), 6-3, 6-4 victory over Spain's Fernando Verdasco.

Wawrinka, the defending champion and this year's fourth seed, cruised to a 6-4, 6-2, 6-4 triumph over Finnish veteran Jarkko Nieminen.

Djokovic has yet to lose a set in his first three matches. The four-time champ barely broke a sweat this week before Saturday, dropping a total of 14 games in his first two outings.

Verdasco, though, made him work in the first set. A semifinalist in 2009, the 31st-seeded Spaniard matched Djokovic for 60 minutes before finally faltering in the first-set tiebreak. The Serb then broke once in each of the next two sets to finish in 2 hours and 21 minutes.

"It was the turning point probably, winning the tiebreaker as close as it was," said Djokovic. "I thought it was a good match. It was a big challenge for both of us. He was a former top-10 player. Somebody that loves playing on the big stage, a powerful game. I'm glad to go through in straight sets."

Verdasco slammed 10 aces in the opening set, but did himself in with 28 unforced errors. Djokovic had 12 unforced errors of his own in the first set, but had just 12 more the remainder of the match.

Next up for Djokovic will be Gilles Muller, as the lefty from Luxembourg ousted American John Isner in straight sets, 7-6 (7-4), 7-6 (8-6), 6-4.

Wawrinka ended Djokovic's three-year run as Aussie Open champ last year in the quarterfinals and went on to capture his first career Grand Slam title. The Swiss veteran has yet to lose a set this week, as well.

On Saturday, Wawrinka blasted 55 winners to just 18 for Nieminen

"It was a really good match from me today," said Wawrinka. "I was playing great, tried to be more aggressive than normal."

A familiar opponent awaits Wawrinka in the fourth round, as Spain's Guillermo Garcia-Lopez advanced Saturday with a 6-2, 6-4, 6-4 rout of Canada's Vasek Pospisil. Garcia-Lopez knocked off Wawrinka last year in the first round of the French Open.

"He's been playing really good," said Wawrinka of his fourth-round foe. "I saw him a little bit this tournament. I lost against him last year French Open first round. We had some tough battles in the past. It's never easy."

Other winners Saturday included U.S. Open runner-up Kei Nishikori, Spain's David Ferrer and Canada's Milos Raonic.

The fifth-seeded Nishikori rallied after dropping the first set against American Steve Johnson, pulling out a 6-7 (7-9), 6-1, 6-2, 6-3 win. Next up for the rising Japanese star will be the ninth-seeded Ferrer, who also went four sets to eliminate France's Gilles Simon, 6-2, 7-5, 5-7, 7-6 (7-4).

Losses Saturday by Johnson and Isner ended the American men's hopes in Melbourne.

The eighth-seeded Raonic also eased into the fourth round with a 6-4, 6-3, 6-3 victory over Germany's Benjamin Becker and will next play Spain's Feliciano Lopez. The 12th seed beat Poland's Jerzy Janowicz, 7-6 (8-6), 6-4, 7-6 (7-3).

Fourth-round play starts Sunday with Rafael Nadal and Andy Murray among those in action. The third-seeded Nadal will square off against South Africa's Kevin Anderson, while the sixth-seeded Murray will close the night session at Laver Arena against 10th-seeded Grigor Dimitrov of Bulgaria.

Andreas Seppi of Italy will try to build off his monstrous upset of Roger Federer, but will likely have the crowd against him when he takes on Aussie Nick Kyrgios. Another unseeded Aussie favorite will also play Sunday when Bernard Tomic faces seventh-seeded Czech Tomas Berdych.