After a measured build up involving the likes of Tom Thorpe and Will Keane, Larnell Cole crossed from the right for Michele Fornasier to score at the second attempt with a volley after his initial header was well saved by Russell Griffiths.
Late in the second-half Jesse Lingard had the freedom of the Everton half when sent clear by Will Keane and the winger kept his composure to expertly slip home the clincher.
United coach Warren Joyce's side will face Brazilians Coritiba in the final on Sunday night with goalkeeper Sam Johnstone looking forward to the contest.
"The Brazilians like to pass but so do we," he told the Dallas Cup official website. "So we'll see.
"It was difficult - we played Everton back home and it was more physical compared to the previous games. We stuck it out and did well. All the lads are fit and kept going until the end.
"We want to win the tournament so we're going into the next game to win."