The midfielder insists his side should not concede defeat in the race with Juventus but refused to be drawn into the controversy surrounding the Turin derby
The Giallorossi currently sit nine points adrift of leaders Juventus, although they do have a game in hand on the reigning champions, but Nainggolan insists they can yet haul in Antonio Conte's men.
"As long as we're not mathematically out of it, we have to believe," he told Mediaset.
Juve's 1-0 win over Torino on Sunday was marred by controversy, with the Bianconeri slapped with a fine for offensive banners in the crowd while the Granata were denied what they believed to be a clear penalty during the game.
Nainggolan was impressed with the way Torino took the game to their bitter rivals but refused to be drawn on the game's more unsavoury incidents.
"I saw the derby between Juventus and Torino. Torino played well, they made it difficult for Juve, but then we don't talk about the other teams," he said.
Finally, Nainggolan stressed he feels he fully deserves a spot in Marc Wilmots' squad in the World Cup despite the fierce competition for places within the Belgium side.
"The abundance of midfielders at Roma doesn't scare me, the Scudetto is long and we must all do our part. The more players, the better - the competition is good for me making the World Cup squad," he added.
"I think I have a chance. In recent years I was given a chance and I have deserved it."