At 176 pounds, Tyric Trapp, a two-time National Golden Gloves champion from Red Bank, New Jersey, made his case for being the best light heavyweight in the United States by stopping Doniyor Mannopov, of Algonquin, Illinois, in the third round. Trapp, 25, felt short-changed after last year’s National Championships, when he was dominating his first-round opponent, only to have the fight stopped when his tooth was knocked out of his mouth.