This episode is unique because it is split between filler and manga-canon content:
After leaving Warship Island, the Straw Hat crew is confronted by Eric the Whirlwind, who attempts to steal the "Dragonite" (fossilized dragon bones) from the Sennenryu. One Piece Episode 61
Luffy takes on the fight personally, fulfilling a promise to the dragon Ryu. He eventually defeats Eric by knocking him off the ship as they approach the Grand Line. This episode is unique because it is split
Episode 61 is a pivotal transition point in the One Piece series, serving as both the finale to the anime-original Warship Island Arc and the official beginning of the Reverse Mountain Arc . 1. Plot Overview One Piece Episode 61
Concludes the anime-only Warship Island story, including the final defeat of the antagonist Eric.