He recovered from having to take a standing eight count in the first round of the 160-pound junior-division championship fight to win a decision over Paul Johnson in Richmond, Va.
"I did think I was in trouble," Decker said. "After that first round, I was like, man, I came all this way and I'm losing. Then everyone else started yelling at me, 'This is the final, get busy, get to work.' So I thought now it's time to take care of business."
Thiago Azeredo, who trains Decker at Sitan Gym in Chandler, said the young fighter won in spectacular fashion.
"He was the only one who fought three times that day," Azeredo said. "He got knocked down in the first round, so he really went at it hard in the third round. He put a beating on the other kid. Even with the knockdown, everybody knew Jordan was going to win the fight."
His performance at the North American championships earned Decker a spot on the U.S. team for the world championships taking place in Scotland in October.
Decker, who just started his senior year at Mesa's Dobson High School, is trying to raise $4,000 to pay for the trip to Scotland for himself and Azeredo.