User blog comment:Miskos3/Fairy Tail 542: Instinct, Review/@comment-1248963-20170703205452/@comment-7418318-20170706075635

While I generally agree on your point of the motion sickness being retconned in (thought at least this retcon didn't contradict anything established, so it isn't as bad as some others), to be fair Gajeel had a lot of advantages over Natsu in the Phantom Arc.

Natsu had already had a very tough fight against Totomaru in which he took quite a bit of damage, then was beaten to a bloody pulp by Aria and finally had at least some of his remaining magic power ripped out of him right before Erza swooped in to save him.

And after all that the well rested and completely fresh Gajeel came out equal or slightly below Natsu and had to eat his element to gain the upper hand.

I think that shows that Natsu was indeed quite a bit more powerful than Gajeel in the Phantom arc and would have quite handily sent Gajeel packing if the fight had been a fair one.