is one piece episode 24 filler?

Yosaku explains how he and Johnny lost the Going Merry. While their backs were turned to her, Nami pushed them both overboard.

Stating she needed to take care of "business," she drove the ship away, leaving the crew behind. Almost immediately after Johnny and Yosaku fell into the sea, they witnessed the Krieg Pirates' flagship be destroyed.

Zoro recognizes the assailant as Dracule "Hawk-Eyes" Mihawk, rumoured to be the world's greatest swordsman. Mihawk states that he attacked the Krieg Pirates simply for his own amusement.

Zoro immediately challenges him to a duel, to which he accepts.