The team, coached by Swede Pia Sundhage, start their Olympic campaign against France in Glasgow on Wednesday, two days before the opening ceremony to the London Games. They will also play North Korea and Colombia in the group stage.
While the United States are the defending champions and highly fancied to win a third consecutive gold medal, they come into the tournament still with some of the bitter taste from last year's World Cup campaign in Germany.
Japan fell behind in regulation and extra time during last year's final but fought back on both occasions for a 2-2 draw before prevailing 3-1 on penalties over a top-ranked US team.
"Because we got so close and lost in the most dramatic way you can lose a football tournament, it adds even more fuel to the fire," Wambach, who has 138 goals from 182 internationals, said.
"We have had a short period of time from the World Cup to now and I think it is really nice and important for the freshness of that loss to be stuck in our minds and honestly in our hearts.
"What is in the past, is in the past but this team still has something to prove."
While success in the Olympic tournament, allied with World Cup triumphs in 1991 and 1999, makes the US squad one of the dominant forces in the women's game, Wambach believes that the current crop are fired up to show their value.
"There is no better motivation than losing. I think that we did a lot of really cool things in Germany last summer, we got people excited about the women's game again and truthfully I wasn't sure if that was going to happen again in my career.
"This team has something to prove. I know that all of us are competitors through and through. We are competing when we are playing ping pong in our team floor, whatever it is we want to win," she said.
Morgan scored in the World Cup final but until this year was mainly used for the bench before her form forced Sundhage to adjust her system.
"She provides speed and she is playing very well together with Abby," said Sundhage. "This team different from the World Cup, a different team and the way she has been playing recently not only gives her confidence but also the whole team."
Wambach, who compared the partnership to the one she enjoyed with Mia Hamm in the past, said Morgan had made a breakthrough in terms of self-belief.
"Alex has had probably the biggest improvement in her confidence, I told her time and again, when she scored the big goal that won us a game, 'put that in your back pocket,'" said Wambach.
"As a forward when you have times when you aren't scoring, you have to remember the times that you did, especially the big ones.
"Her confidence has been the turning point in her career, much like my confidence was after 2004 did a huge service for me and my career - I think Alex will continue to grow, she has had a fantastic year."