If expectations in his native Argentina are anything to go by, then Juan Martin del Potro already has the Australian Open title all wrapped up.

In September, the 22-year-old became the first player to beat world number one Roger Federer and Rafael Nadal in the same major on his way to the US Open crown, earning him the country's sportsperson of the year award ahead of Barcelona forward Lionel Messi and golfer Angel Cabrera, winner of the 2009 US Masters.

He also made his first Masters event final, losing to Andy Murray, and ended the year by reaching the decider of the World Tour Finals in London.

Del Potro finished 2009 as the youngest player in the top 10, at number five - and with it a whole new raft of expectations.

The Argentinian is seeded fourth at Melbourne Park, having crept past Murray in the world rankings after the Scot's decision not to defend his title in Doha last week.

But the man himself says any talk of title favouritism heading into next week's Australian Open is premature.

"I feel the same. Nothing changed for my life after the US Open," Del Potro said after opening his 2010 campaign with a convincing 6-3 6-3 win over Croatian Ivan Ljubicic at the AAMI Classic at Kooyong today.

"I still have the same friends and parents and coaches, and that's important.

"I'm in good shape. I hope to have a good tournament next week.

"I feel good with my tennis, I feel confident. I don't know if I'm favourite."

Despite having just 10 days off over the off-season, Del Potro showed no signs of fatigue as he strolled to victory over Ljubicic, his first competitive match since losing to Nikolay Davydenko in the season-ending championships in November.

"The conditions were tough, a lot of wind. I returned very good, served good. That's important for this kind of match, this kind of surface. It's a good victory for the beginning of the season," he said.

Del Potro believes he finally has the weapons to mix it on the big stage.

"Of course to beat Roger in the final (of the US Open) gave to me a lot of motivation and confidence to keep working, keep trying," he said.

"When I go onto the court with Roger and Rafa, I don't feel too much different, and that's important for my career, for the future.

"I think it's the process. I need time to get experience. I am the youngest player in the top 10. They know how to play finals or Masters Series and I don't have too much experience like them.

"But if I keep working the same way, maybe in the future I will have my chance to be like them."