The National Duel Circuit was a tournament held in Heartland where Shark, Quattro and other Duelists participated, appearing in Yu-Gi-Oh! ZEXAL.
Shark and Quattro faced each other in the tournament's finals. However, Quattro intentionally put his Deck on top of a pot, so that it fell and wound up scattered on the floor in the break room when Shark passed by it. As a result, Shark was disqualified before unleashing his winning move because he had seen Quattro's Deck before the Duel. Therefore, Quattro was considered the champion of the tournament.