Marcelo says Saturday's 2-1 win over Barcelona at Camp Nou has given Real Madrid belief that they can still win La Liga.
Gerard Pique opened the scoring for Barcelona in the 56th minute, but Karim Benzema restored parity shortly after.
Madrid then appeared to be in trouble when Sergio Ramos received his marching orders after Gareth Bale had a goal controversially ruled out, only for Cristiano Ronaldo to net a late winner.
"Barcelona were 39 games without a loss, but we deserved to win. These are three important points that give us morale to keep fighting," Marcelo was quoted as saying by AS.
"We suffered, Barcelona are one of the best teams in the world, but we deserved to win. The entire team did well, from the goalkeeper to our attackers. It is very difficult to play against Barcelona, but we had our moments on the ball.
"We owed the fans something and we showed what we can do. All teams that play against Barcelona suffer. It is very complicated to play here at Camp Nou. We managed to hurt them with our counter-attacks."
Ramos' 83rd-minute dismissal could have cost Madrid, but Marcelo was quick to defend the centre-back and insisted there is no issue with the Spain international.
"There is no problem with Sergio Ramos," Marcelo stressed.
"He always gives his all for the team."