The United States opened their World Cup campaign with a 4-1 win over Paraguay on Friday, powered by a first-half double from striker Folarin Balogun, but the victory was tempered by concern over the fitness of Christian Pulisic. The emphatic Group D win marked a dream start for the co-hosts, whose four goals were their most ever in a World Cup match. Balogun became the first US player to score twice in a World Cup game since the 1930 tournament.