"In 2012 there was a question about the car, but this year we do not have to worry about being two and a half seconds behind," the Spaniard added at the Madonna di Campiglio media event.
As for his 2013 rival, Alonso acknowledged the achievements of Red Bull's Sebastian Vettel but insisted he thinks Lewis Hamilton is better.
"I don't know who will be the main adversary," he is quoted by AS newspaper, "as it will be the strongest team and car, with the greatest luck and all the other factors.
"If you ask me who is the strongest driver it is Hamilton. It is a personal opinion, nothing to do with politics or psychological warfare.
"I'm not saying Vettel is not strong, in 2011 his performance was fantastic, although it is true that his car was much faster."
Alonso, however, repeated his claim that he thinks Briton Hamilton - his McLaren teammate of 2007 who this year has moved to Mercedes - is stronger than Vettel.
"I'm sure he (Hamilton) can win this year, he is a super driver who has won with whatever car he had in all the different years.
"I am sure that with Hamilton, Mercedes will be stronger and will win races this year."