Ferrari seemed set to drop Massa as he struggled through the 2012 season, the third year in a row that he had been overshadowed by team-mate Fernando Alonso.
But the Brazilian held on to his drive and became increasingly strong in the final races, amid a change in mental approach that Massa feels will continue this year.
"What we have done in the second part of the championship was a bit of training for this season," Massa said at the Wrooom media event, attended by AUTOSPORT.
"I want to be competitive from the start to the end, I want to return to winning and also hope to be able to fight for the championship.
"I have done this in the past, I have not forgotten this."
Massa said his mid-season turnaround last year was almost entirely due to psychological progress rather than car changes.
"It is not that the car changed that much from August in reality," he admitted. "There was also a change from my side."
The Brazilian explained that shutting out criticisms and remembering what he had achieved in his best days proved key.
"Even if 90 per cent of people do not want to believe in me any more, it is important that you believe so you are not good one day and bad the day after," Massa said.
"You need to believe in what you can do. I believe in myself, I know I can be a champion, I know I can win, I know I can be what I was all my career.
"I think after you understand yourself it makes you stronger and stronger all the time."
Massa feels he has recaptured the happiness he felt when fighting for the championship in 2008.
"Maybe I was not enjoying my job so much, maybe I was not happy," he mused. "I am happy now. When you get into the car and want to have fun and enjoy it, that is when you can do your job in the best way possible.
"By doing that you can have a year like 2008."