A day after Germany midfielder Bastian Schweinsteiger called the Argentines "disrespectful," his captain said they did not know how to deal with a defeat.
"Bastian said what he said. We know South Americans are impulsive and temperamental and cannot lose," said the usually soft-spoken Lahm.
"We will see on Saturday how they will lose and how they will behave after a defeat," he said.
Germany beat Argentina in the 2006 World Cup quarter-finals on penalties before a violent brawl broke out at the end of the match, drawing in most players and coaches from both teams with punches and kicks flying.
The two sides have also met twice in a World Cup final, with Argentina winning their second trophy in 1986 and Germany coming out on top in 1990 for their third World Cup victory.
"We have to concentrate on our football only," said Lahm. "The South Americans are temperamental. We know that and we will see how they will deal this time with a defeat."
"It is time we beat a top team. Our young team has to show that it can beat a top team like Argentina in 90 minutes," Lahm said.
DISRESPECTFUL
Schweinsteiger had kicked off the unusual war of words on Wednesday saying Argentine players were always trying to influence the referee to gain an unfair advantage.
"It starts before the match," Schweinsteiger said. "If you see how they gesticulate, how they try to influence the referee. That is not part of the game. That is a lack of respect. They just are like that," said Schweinsteiger.
Team manager Oliver Bierhoff, playing the role of a good cop, urged German players to forget the 2006 World Cup brawl.
"We should leave it behind and keep a cool head and just concentrate on what we do best," he told reporters, sitting next to Lahm.
"I do not think it will be a fiery game," he said adding Germany were not overestimating their abilities despite having played a good tournament so far.
"That is exactly the strength of the team. That they have a healthy self-esteem. This enthusiasm around them will not carry them away thinking they have reached their target."
