Katakuri vs Luffy: Why Katakuri is so strong now..?

As Luffy want to save his Nakama..
He turn the fight against Katakuri, one of Sweet Commander in Mirror World..
But why Katakuri seem so strong right now..?
And why he can stop Luffy's attack by copying Luffy's attacking style..?

Are we underrated on Katakuri since he fears as he saw something during that wedding..?
Or something else..?

There is one thing for sure that come to my mind about this..
Let me explain it to you guys..
That one thing is..
But..
Let explain more on Katakuri first..
He's one of Big Mom's Sweet Commanders..
The highest bounty of them all..
Although he's also got Mochi DF that sticky and immobilized his opponent and only can be stop by water..
He also the one that equipped with Observation Haki..

So..
The fight between Luffy and Katakuri in Mirror World provide advantage and disadvantage for Luffy..
- The advantage is the weakness of Katakuri's DF is water.. As what Jimbe did before at Tea Party.. So.. Luffy could do the same as what he did to Sir Crocodile that also got the same weakness as Katakuri.. Luffy used water and also his blood to fight Sir Crocodile.. Maybe this would be the advantage for Luffy in that fight since Mirror World don't have water.. Or perhap Luffy manipulates Brulee so that Mirror World could be flooded by sea water as we all knew that Brulee want to sent soldier to Thousand Sunny and during that time Big Mom's creates Tsunami to hit Thousand Sunny.. This would be the only chance for Luffy to fight Katakuri.. But if this happen.. Luffy is saved by the bell because he don't need his strength at all as Mirror World been flooded by sea water and Katakuri is weak to it.. Yeah.. Luffy also weak against sea water but what he need is to grab Brulee.. She the only key to survive..
- The disadvantage is the Katakuri could easily copying Luffy's attacking style by using his Observation Haki.. Yeah.. He can see the near future.. So he can predicted it.. This is crucial because he just need to focus on Luffy.. So this would be disadvantage for Luffy.. But.. I bet Luffy would have something in his sleeve.. He just need the right moment to hit Katakuri.. (I don't know why but I think Katakuri will fight against Sanji in future episodes as the battle of Observation Haki will took place..lol) But the outcomes of Sanji vs Katakuri is Katakuri want Sanji to take care of Pudding as he knew that Pudding would be happy to have Sanji or to travel with Strawhat Pirates.. (I don't really want Pudding to be the next female Nakama.. But she could be Sanji's wife/partner that travel with Sanji)