Hayden sees Stoner as title threat

"There is still a long way to go in the season, but I remember that winning my first race made a big difference to me," the American told a news conference in Madrid.

"He's definitely got the skills and the speed to win the title, and he was very solid last week. It was only the first race of the year but it could be the step up he needs."

The 21-year-old Australian held off former world champion Valentino Rossi in the season-opener in Qatar to become the first winner on the new 800cc machines.

The Ducati rider finished eighth in his first season in MotoGP last year, after an impressive campaign.

Hayden, 25, only managed an eighth-placed finish in Qatar, but denied that the shoulder surgery he underwent at the end of last season influenced the result.

"It has maybe taken me a little longer than was expected to recover from it. There are still some things I can't do in the gym and I am a little restricted in some of my movements," Hayden said.

"But I am not using that as an excuse, I feel fine on my bike."

Hayden and his Honda teammate Dani Pedrosa were speaking at a promotional event in Madrid ahead of the Spanish Grand Prix in Jerez next weekend.

After the news conference, the six Honda team riders mounted their bikes to make a tour of the city centre streets, shattering the peace of a Sunday morning.