Rafael Nadal insisted his back was "not perfect" but he is hoping the injury improves after easing through the Australian Open first round.

Playing his first competitive match since last year's ATP Finals, Nadal cruised past Laslo Djere 6-3 6-4 6-1 on Rod Laver Arena on Tuesday.

As he eyes a record 21st grand slam title, the Spanish star entered the year's first major under an injury cloud.

Despite his comprehensive first-round victory, Nadal, 34, said his back was still troubling him.

"My back is not perfect, as I said a couple of days ago. Every day that I'm able to go through, probably there are more chances to get better. That's the thing now," he told a news conference.

"There is always a chance to improve, and that's why I'm here playing and fighting to try to get better and then give myself a chance. Today it's not great.

"I needed to change a little bit the motion of my serve. That's what I tried to survive that condition today. Tomorrow a day off.  After tomorrow, another match. I need to go day to day and just try to stay positive.

"Of course every day that I am trying to stay here longer is a day with a chance to get better finally, so that's what I am trying. Trying to do all the things possible to be ready for compete, for what I came here."

Nadal won 40 of 48 points on first serve against Djere, while he mixed 19 winners with 24 unforced errors.

The world number two is bidding to become the first man in the Open Era to win every grand slam at least twice as he aims to add to his 2009 Australian Open title.

"I was able to win in straight sets. It's always a positive start for me," Nadal said.

"Always difficult after not playing for a while, playing an official match in a while. A good start. Happy.

Nadal will face either Viktor Troicki or Michael Mmoh in the second round.