The defender says there will be no wild celebrations after Germany's destruction of Brazil, calling on his teammates to focus on the final.
Germany earned an incredible 7-1 win over the tournament host in Belo Horizonte on Tuesday, with Toni Kroos and Andre Schurrle scoring twice and Thomas Muller, Miroslav Klose and Sami Khedira adding to the score sheet before Oscar's consolation.
But Hummels stressed that Germany is already concentrating on the next fixture.MORE: Beautiful people in Brazil | USA MVP rankings
"We think of it now, enjoy it and show our best on Sunday," the 25-year-old defender told reporters. "It was surprisingly quiet. You can also say without being arrogant — we have known for over an hour that we are through and that is different from tight games when you feel high emotion at full time.
"This is really something special, what each individual has done. And we will now try with everything we have to have to make the big dream come true."
Toni Kroos echoed the thoughts of his compatriot, stressing that the final was now the sole concern despite the impressive result against the Selecao.
"We have played a great game, we have almost overrun them at the beginning," he said. "We have had an incredible game but another game is still waiting. We are here to win the World Cup, we are not yet there."