The Blaugrana are currently four points behind the Liga-leading Blancos, but a 7-0 win over Osasuna on Sunday has breathed new life into the Catalans' bid to defend their Spanish title.
"Now comes the most difficult game of the season but also the most beautiful one,” the midfielder told Sport.
“We want to get a good feeling at the Bernabeu and we believe that we can win there.
"The Madrid-Barca game is a war of football, but what has happened in the past has stayed there.”
While they can propel themselves right back into the title race with a win in the Spanish capital, Iniesta admitted that things have not gone according to plan for Barca this term.
"It has not been a comfortable season," the World Cup winner confessed. "At all levels, there are many reviews, changes to be made - it has been difficult."
Iniesta scored in Barcelona’s 7-0 thrashing of Osasuna and celebrated the goal by sending a kiss up to the sky in memory of the child he and his wife lost last week.
"When one bad thing happens and you have a low moment, you realise the love of anonymous people and that gives you a lot of strength. My wife and my family appreciate all the love of these people," he said.
“I have received expressions of affection from the players of Real Madrid; there are more important things than a football game.”