Low told reporters on Tuesday that while Spain were essentially the same world-class team that beat them 1-0 in 2008, Germany had made big strides.
GEAR:Get your Germany shirt
"Two years later for us there are many changes while the Spaniards are similar. We have made progress in the style of football we play and the results we get," he said.
"We were not as consistent and our quality was not as good. Now our combination is much better as is our flowing game."
Low's view was also shared by his Spain counterpart only minutes later.
"They have undertaken a renewal with an important base of young players. They have conserved their values and added players of technical quality. They make a good mix," said Vicente del Bosque, who took over the team after their 2008 victory.
GERMAN VISION
"First of all it is us who have to play our game. Everybody knows Spain. We have our own ideas and we want to impose our own playing style on the game," Low said.
Low said he had no doubt Germany's youngest World Cup squad in 76 years would rise to the occasion.
"Have I doubted them until today?," Low said when asked whether his young team could step up to the plate in what is the first major tournament for many of his players.
"So why should I do it today?" he said.
Germany have been the most exciting team to watch in the tournament, firing four goals past England in the second round and Argentina in the quarter-finals. They have so far only conceded two goals in five matches.
"We know the Spaniards have been playing together a long time and they are the team that makes the fewest mistakes. Hardly any.
"But we have the confidence to know that we have the power and creativity and if we can cause problems in their game development, we will get our chances," the 50-year-old said.
"We know we cannot pin them back throughout the match but we have to force them back ... and use every chance to attack," he said.
Low will have a full squad to pick from, apart from suspended striker Thomas Muller. Either striker Cacau or one of Toni Kroos and Piotr Trochowski would replace him with a decision to be taken just before the game.
"The mood is good but not euphoric. I see concentration and feel that everyone involved wants more. The aim can only be one: to win this game and climb this mountain."
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