Melbourne- Rafa Nadal savoured the best win of his campaign at Melbourne Park in felling South African Kevin Anderson 7-5 6-1 6-4 to storm into the Australian Open quarter-finals on Sunday but was reticent to talk up his chances of a 15th grand slam title.

On the comeback trail after illness and injury, the Spanish third seed wrote off his chances in the lead-up but now finds himself in the last eight with energy to spare after needing little more than two hours to despatch the 6ft-8in (2.03 metre) Anderson on a cloudy day at Rod Laver Arena.

Nadal will play Czech seventh seed Tomas Berdych for a place in the semi-finals, and will surely feel confident against a man he has beaten in their last 18 encounters.

"(Berdych) is playing great. Will be a very tough opponent, no?" Nadal told reporters.

"But for me, quarter-finals is a great result, talking seriously. Arriving here, losing in the first round of Qatar, not playing matches for the last seven months, to have the chance to be in quarter-finals again here is a very positive thing for me.

"I try to play better and better every day. If that happens, I hope to keep having chances for the next match.

"But today is a day to be happy the way that I improved my level of everything... all the things I have to do on court."

Nadal had to weather an early serving storm from 14th seed Anderson and was forced on the back foot by his rangy opponent at 5-5 in the first set, who prised five break points from the Spaniard in the 11th game.

Nadal would save them all by mixing a string of crunching serves with forehand winners, rattling Anderson who was promptly broken in the next game when he dunked a regulation volley in to the net.

"So (I) just tried to play with the right decision, right determination, and I did. Worked well. But sometimes works well, sometimes doesn't," Nadal said.

From there, Nadal completed an eight-game tear to take complete control of the contest and after an early break in the third set, cruised to victory, preserving himself for a possibly tougher encounter against hard-hitting Berdych.

"Doesn't matter what happened in the past. It's a different story this time," said the Spaniard. "Different moment for me; different moment for him.

"He's a great player. I have success against him, but I have (had) the chances to lose against him."