One Piece Chapter 38, page 13-15: PIRATE FLEET

Kuro is insulted by Luffy's comparison, asking, "WHAT? YOU SAY THAT I AM INFERIOR TO THAT 'CAPTAIN' IN A KID'S PIRATE GAME?" Luffy replies, "THAT'S RIGHT." Kuro bursts into hysterical laughter: "HA HA HA HA... YOU'RE SO STUPID! DON'T GET COCKY JUST BECAUSE YOU'VE BROKEN MY 'CAT'S CLAWS'. IN WHAT WAY AM I INFERIOR TO HIM!?!" Kuro then begins to sway side to side, preparing a technique.

Luffy answers Kuro's question: "THE WAY YOU THINK. YOU DON'T KNOW WHAT A TRUE PIRATE IS SUPPOSED TO BE!!!" Before Kuro can react, Luffy lands a powerful punch right to Kuro's face with a loud "DOKA!!!

Kuro is sent flying backward by Luffy's punch. The pirates are amazed, shouting, "THAT KID... HE SAW THROUGH THE CAPTAIN'S 'SILENT STEP'!!" Kuro slowly gets back up, wiping blood from his mouth, and growls, "YOU'VE INSULTED ME...!!! YOU WANT TO KNOW WHAT A TRUE PIRATE IS SUPPOSED TO BE? THEN LET ME SHOW YOU... TOGETHER WITH THE TERROR OF A REAL PIRATE!!!