
The 14-time Grand Slam champion defused big-serving South African Kevin Anderson 7-5, 6-1, 6-4 in 2hr 6min on Rod Laver Arena to advance to the last eight of the year's first major tournament.
Nadal, who conquered Roger Federer in the 2009 Melbourne final, will next face Tomas Berdych. He has an intimidating 18-3 record over the Czech seventh seed who has not beaten him since 2006.
It will be Nadal's eighth quarter-final appearance as he bids for his second Australian title after losing to Stan Wawrinka in last year's decider.
Nadal looked in far better shape after the dramas of his five-set dogfight with American qualifier Tim Smyczek in the second round where he struggled with cramps and dizzy spells.
"For me the quarter-finals is a great result," Nadal said.
"Arriving here, losing in the first round of Qatar, not playing matches for the last seven months and to have the chance to be in quarter-finals again here is a very positive thing for me.
"I'm very happy for that. I am sure that is going to help me for the next events. For sure I am going to try my best. I will try to play better every day. If that happens, I hope to keep having chances for the next match."
It was an altogether different Nadal who was looking forward to the second week of the tournament and the looming battles, with the popular Spaniard delighted to have taken a step forward after the uncertainties of the earlier rounds.
"Today is a day to be happy with the way that I improved my level of everything, all the things I have to do on court," he said.
"I was closer today. Even if I played the first two sets well the other day, today I was much closer to what I have to do to have success.
"It was probably my best match here this year so that's very important for me and very special." AFP