Worth, competing in the 19 and over category, was only beaten by Loughborough’s Toby Robinson in the 5km race a Rother Valley Country Park.
Robinson clocked 56 minutes and 49.9 seconds, with Worth coming home in 57:39.9.
There was also a top five finish for Worth’s Mount Kelly team-mate Alexander Seymour in the 16-year-old boys’ 3k race. He came home in 37:53.40, with Caradon’s Travis Bramley, the national youth triathlon and aquathlon champion, finishing 10th in 40:48.82.
Plymouth Leander’s Ethan Rayment finished ninth in the 14-year-old boy’s 1.5km race in 19:13.73.