Sounding at times as if they had already won the match, the two players told reporters at their team base that Germany have more talent, more experience, an extra day's rest and more than enough confidence to beat Argentina the way they did in the 1990 final and the quarter-finals in 2006 and 2010.
"We're here to win the World Cup," said Lahm. "We all enjoyed watching the (Argentina-Netherlands) semi-final on TV and it didn't matter to us at all who we'd play in the final."
Lahm said Germany players not only have more experience in the latter rounds of the World Cup that will help on Sunday but also every player on the team has played in the finals of the Champions League, German Cup or cup final in England.
"The experience we've got all the way through our team is definitely an edge for us," he said.
"A lot of our players have experience in important final matches with their clubs and it doesn't always matter if they won or lost. I think that deep experience everyone on our team has is definitely important for a tournament like this."
Mueller and Lahm even answered questions at times about how they planned to celebrate the victory on Sunday.
Mueller said that there was an abundance of confidence on the team with its "golden generation" that has made it to at least the semi-finals of the last four World Cups and the last three European championship tournaments.
"I've been telling friends back in Germany on the phone that we're going all out here so that you can keep having those big barbecue parties in Germany to celebrate during the best time of the year in Germany," said Mueller, who also had no doubt about the outcome on Sunday.
"I'm not expecting that we'll be ahead 5-0 at half time again like against Brazil even though that would be nice," Mueller said, reflecting a growing smugness and optimism back home in Germany that it's no longer a question of "If" but only a matter of "by how many goals" they'll win.
"It could end up being a tight match like against Algeria or France. But it doesn't matter. We know what we have to do."
Mueller said the team are looking forward to returning to Rio de Janeiro for the final after beating France there in the quarter-final 1-0 but said they're not going to see the tourist attractions.
"Unfortunately we won't be going to Rio to take a guided tour or to get to know the magic of the city," he said. "There's only one reason to go there: to pick up the World Cup trophy. We know what we have to do."
Mueller, who has five World Cup goals here, said scoring again in the final would help the team beat Argentina as well as help him win a second Golden Boot for most goals scored after he won it in 2010 with five goals.
"If I score that'll help in both competitions," he said, but added winning the World Cup was more important to him. Mueller offered his ideas on how to stop four-time World Footballer Messi.
"We've all got to stay on his heels and try to keep disrupting him. As soon as he gets away from one of us, the next guy has to jump in and be on him and so on until we get the ball back. It's important to defend collectively as a team against him but without losing sight of the other Argentina players."