England C were beaten by Portugal in the International Challenge Trophy final at Sixfields.
England and Ebbsfleet keeper Preston Edwards denied Yannick Djalo early on, and England spurned two good opportunities from free-kicks.
When Lewis Fernandes hit the post with a second half free-kick, the rebound was bundled home by Johan Tavares.
England could have forced the game into extra time but Andy Mangan fired just wide of the far post in stoppage time.
Paul Fairclough's side, missing six Luton Town and AFC Wimbledon players because of Saturday's Blue Square Bet Premier play-off final, won the tournament in 2006, beating the Netherlands 4-1 at Burton Albion's Pirelli Stadium.
England: Edwards, Vaughan, Franklin (Blair, 65), Atkinson, Porter, Wylde (Coulson, 76), Mangan, Rose (Byrne, 80), Donnelly, Simpson (Styche, 70), Clancy. Sub not used: Hedge.
Portugal: Ventura, Gongalves, Carrico, Tavares, T Pinto (Marques, 84), Coelho, ,Djalo (Rui Sampaio 90), Castro-Pereira (Y Pinto, 77), Saleiro (Gomes Silva, 77), Santos, L Fernandes (Candeias, 84). Subs not used: Felgueiras, Fernandes.