Round 1 - Luffy couldn't do anything against Crocodile
Round 2 - Crocodile didn't expect Luffy to be able to Harm him so He received few Attacks, but once He decided to get Serious (Telling Robin to leave), the Fight was Over in no time
Round 3 - Again Crocodile got hit multiple times because He didn't expect Luffy to be able to harm him, but even then He still won again & Luffy was on the ground Poisoned
The Fight was completely Normal, nothing Unusual, just Crocodile caught by surprise Twice, but He Defeated Luffy Three Times with Minimum Effort, meaning He won by only using a Fragment of his Power in all Three Rounds
Only Part that is Unexplained till this day, is how did Luffy stand up after getting Poisoned, and ended up Defeating Crocodile in an Overwhelming way (Even bypassing his Blade, something that Luffy cannot normally do), that Round 4 is only thing that doesn't make sense in the entire Fight
However, in previous Arc, Dorry/Brogy said that when Two in Elbaph Fight, their God grants Divine Protection to one of them, and that's exactly how it felt in Luffy vs Crocodile, Luffy was granted Divine Protection, i don't know how it works exactly, and i don't know which God are Dorry/Brogy referring to, but i believe we will get our Answer in this Arc
Pre-TS Luffy was No Match for Crocodile, only Round 4 was Puzzling & requires an Explanation this Arc.