Nadal feeling good despite preparation worries

World number one Rafa Nadal believes he is ready and in decent form ahead of the Australian Open.

The Spaniard withdrew from tournaments in Abu Dhabi and Brisbane after beginning his preparations for 2018 later than usual amid reports he was still struggling with a knee injury.

For the first time in his career, the 16-time grand slam champion will head into the year's opening major without playing a competitive match in the lead-up.

Despite that, Nadal, 31, said he felt in decent enough form ahead of a first-round clash against Víctor Estrella Burgos.

Nadal: "It's a new situation for me, but I feel good"

"It's the first time I am here without playing an official match in my career. It's a new situation for me. But I feel good," he told a news conference on Saturday.

"I feel that I had a good week and a half of practices. I still have this afternoon and tomorrow, the last practice before the competition starts for me.

"I really hope to be ready. I feel myself more or less playing well."

Nadal almost claimed a second Australian Open title last year, only to be edged by Roger Federer in a thrilling final.

But the 2009 champion dismissed suggestions that result gave him additional motivation this year.

"It's impossible to be more motivated than last year or any year. For me, the Australian Open always, if you are not enough motivated, 100 per cent motivated to play this tournament, probably you don't love this sport," Nadal said.