Ruthless Nadal crushes Carreno Busta to reach last 16

Top seed Rafael Nadal routed fellow Spaniard Pablo Carreno Busta for the loss of just seven games Saturday as the world number one revved up his bid for a 20th Grand Slam title.

The 33-year-old was in virtuoso form to charge past the 27th seed 6-1, 6-2, 6-4 in hot sunshine on Rod Laver Arena and make the round of 16 at Melbourne Park for a 13th time.

"My best match of the tournament so far, without a doubt," said Nadal. "I'm improving every day, so super-happy.

"I did well on my serve and hit good forehands down the line, which is a key shot for me." Nadal joined defending champion Novak Djokovic and great rival Roger Federer in the fourth round with a potential showdown next with Nick Kyrgios.

The Australian, who disparagingly labelled Nadal "super salty" last year, and mimicked his serving routine during his second-round clash, meets Russian Karen Khachanov later.

Nadal, a finalist last year when he crashed to Novak Djokovic in straight sets, was far from clinical in his previous match against Federico Delbonis, winning only three out of 20 break points.

But his conversion rate against his Davis Cup teammate was much better, putting away five from 10 in a dominant display from the 2009 champion.

He broke Carreno Busta on his first service game to immediately take charge, dictating the rallies and forcing his opponent around the court.

Carreno Busta became a spectator as Nadal raced through the set in 29 minutes and he then broke again early in the second set to inflict more pain.

Nadal's relentless consistency was too much for the 28-year-old, who had no answers to the constant pressure and pinpoint service returns that were a trademark in the easy win.

If Nadal clinches a second title in Melbourne, he will equal the 20 Grand Slam crowns held by Federer.

Victory would also make him the first man in the Open era -- and only the third in history -- to win all four Major titles twice, after Roy Emerson and Rod Laver.