User blog comment:IamJakuhoRaikoben/Chapter 464: Natsu vs Zeref, Review./@comment-26451407-20151201010113/@comment-24546844-20151201011349

Debatable. He was overwhelming Zerf with a flurry of attacks but wasn't really hurting him. Zeref doesn't make the fighter type so someone with a good combat experience can dominate him in a fight, but that doesn't mean that they can defeat him. At least that's how I see.

And even then, Natsu was powered-up by an exterior source that he himself said is temporary and we can't really measure his power without it or say if his previous displays were influenced by it. And we haven't seen the extent of the power of the other two to make a comparassion.