The Brazilian says Los Blancos will keep fighting for wins even though they have a 13-point advantage over their nearest rivals Barcelona in the race for the title
Off the back of Los Blancos comeback 3-2 win away to Real Betis, the Brazilian believes second-placed Barcelona should not be disregarded.
"We have [more than] a 10-point cushion, but the league isn't over yet and we must continue fighting to the end," he told the club's website after the win.
The 23-year-old said he respected Betis coming into the match, despite the home side sitting in 13th place.
"We knew it would be tough, but we had to concentrate because they could always score. We had to be ready. Betis are very good at their stadium," Marcelo said, adding Real were fortunate to not have a penalty awarded against them in the dying moments.
"Handballs happen and we just have to focus on playing our game.
"These things are sometimes called for us and others against us. It happens. We just have to be ready to play."
"We're playing well. I'd rather not score and have the team win a match. Our [Champions League] match against CSKA will be decisive and difficult," Marcelo added.
Real Madrid's game against the Russian club kicks off on Wednesday at 20.45CET.