User blog comment:IamJakuhoRaikoben/Chapter 245: The Unbranded Man, Review./@comment-2220139-20110731043017/@comment-3987368-20110731140044

I don't think he nullified it since he didn't realize what it was right away. Zancrow's flame, while a 'God Flame' was still a flame nonetheless so I think that's why Natsu managed to do that, due to his experience with fire.