User blog comment:Ultimate Law of Kaitlyn/Why I think Crocodile losing to Luffy was a fluke/@comment-3119203-20120610163332

I understand what you are saying, and I think that Luffy got incredibly lucky to beat Crocodile. However, Crocodile was stupid when he didn't surely kill Luffy both times. Crocodile was overconfident, and this became his undoing. Luffy could have gotten all the luck in the world, but it would have been worthless if Crocodile had just killed him the first or second time.

As far as your theories concerning Crocodile having better knowledge of his fruit than the admirals, I think that is debatable. Crocodile has mastered all aspects of his fruit, but the admirals are admirals for a reason, and all three of them were extremely proficient in using their abilities to their full advantage (even Kizaru, who's a bit slow in the head).