is one piece episode 236 filler?

As promised, Usopp returns to Scrap Island at 10pm for the duel with Luffy. Luffy tells him not to have any regrets regardless of the outcome.

Usopp replies that, unlike previous enemies, he is well aware of what Luffy is capable of, and is ready to defeat him. He tells Luffy to come at him with everything he has.

The rest of the Straw Hat Pirates watch from the deck of the Going Merry with varying degrees of concern. Usopp starts with some of the boasts he made when they first met.