The Brazil full-back is upbeat about his current form for Real Madrid, but admits that it is the coach's decision whether he faces the BlaugranaMarcelo says he feels "in good shape" at Real Madrid but that does not mean he will have the opportunity to face Barcelona in Tuesday's Copa del Rey Clasico.
The Brazil full-back, who played 57 minutes of los Blancos 2-1 win over Deportivo La Coruna on Saturday before being replaced by Sami Khedira, appeared reasonably positive about the club's prospects this season and the extent of his involvement.
"I'm in good shape and I'm feeling positive," the 24-year-old told journalists after the game.
"But it's not me who decides whether or not I have to play.
"We have to play to win every game, and that gives us a good feeling-it feels as if we're getting in the mood for some parties."
Los Merengues currently trail Barcelona by 16 points in La Liga, but Marcelo nevertheless stressed the need for defiance within the side, particularly with Champions League and Copa del Rey fixtures on the horizon.
"This win [against Deportivo] lifts our spirits for the difficult matches that we face ahead," he continued.
"We're going to take it one game at a time. We can never give in. While there are possibilities mathematically we have to fight to the end."
Madrid have moved onto 52 points from 25 Liga games and face Barca on Tuesday in the second-leg of their Copa del Rey semi-final tie.