The midfielder knows victory in the El Clasico will throw the title race wide open.
"The truth is that if we want to maximise our options of retaining the league title, we have to win at the Bernabeu. Madrid are leaders and have some of the best players, but form doesn't always count in these games," said Iniesta.
"They are always a difficult team to beat, but I don't think that we'll see the same tension of a few years back on the pitch. It'll be a war, but a footballing war and we mustn't step over that line."
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