Kaka made his return from injury in Real Madrid’s 2-1 win over Zaragoza, scoring in his 15-minute cameo to give Los Blancos the victory.
The midfield maestro then told the media after the game that Real were very much in the title race with Barcelona.
"We are going to fight until the end," Kaka told Marca.
Quizzed about how he would like to silence his critics who have accused him of malingering, Kaka replied: "I know how things work in football. The best answer I can give is on the field.
"I would like to ask Madrid fans not to doubt by injury," he concluded.
The victory keeps Los Merengues within striking distance of Barca, with the Bernabeu boys just a point below La Blaugrana in the La Liga table with four matches left in the campaign.