Bookmakers have the San Francisco 49ers as the heavy favourites for this weekend's Super Bowl clash with the Ravens.
The running back told reporters: "People say maybe against the Broncos, people call it whatever you want, without the pass, we'd lose the game, but we went up there and dominated New England.
"Being the underdog just feels like you have something to prove. If you always put yourself at the top, the only way you can go is down.
"Being the underdog, you have to climb and get to the top, and the only way you can get to the top is winning the Super Bowl."
The two sides last met in 2011, when the Ravens won 16-6.
The Super Bowl takes place in New Orleans on Sunday.