In 1939, Cabaellero engaged an eskrimador named Anoy in what would become one of his notable fights. Anoy, who was from the nearby town of Tangub, was a formidable challenger as he was known to be able to bend an iron bar around his waist using his bare hands. In the duel, Anoy was hit by Caballero in the left hand then in the head and subsequently lost consciousness. The combination of strikes was delivered so quickly that the crowd had not fully understood what had just taken place. This resulted in the misconception that the match was fixed and they began shouting "Tayope!" (fixed). One of Anoy's local supporters attacked Caballero but was fortunately intercepted and subdued with a strike to the hand. Caballero then asked helped from the Philippine Constabulary fearing more reprisals arising from the fight.