LONDON, April 18 : Manchester United's Matheus Cunha struck just before halftime to earn a 1-0 victory at luckless Chelsea on Saturday, taking them a big step closer to Champions League football next season. Cunha fired home from a pinpoint Bruno Fernandes cross with the visitors' first and only shot on target in the 43rd minute. United's interim coach Michael Carrick delighted in Cunha's composure after the Brazilian had missed a chance minutes before. But he had particular praise for his