Casillas saw Real come away from last season with no silverware despite being well placed in three competitions at the turn of the year.
The keeper has admitted Los Galacticos had a below par campaign, but he is heading to Euro 2004 in confident mood.
"It can be a revenge mission," said Casillas. "We (Real) did not obtain anything and what we (Spain) want now is to be the best at the European Championship.
"The team is looking good and we are determined to show our best in Portugal.
"We have had to work hard to get here and that had made us stronger, we have lived through experiences that can help us at the tournament."
