La Roja won Euro 2008, the 2010 World Cup and Euro 2012, but went out in the group stages of the 2014 World Cup and exited Euro 2016 earlier this summer in the round of 16.
"We have a very good base and a really strong group of players, as good as any other nation. We must rediscover the form and hunger that recently allowed our team to conquer the world," Carvajal told reporters. "We know that we have the ability to do so, we just need that little spark to help us."
Spain will take on Belgium in an international friendly in Brussels on Thursday night.