Erick Torres put El Tri ahead in the sixth minute when he outjumped Jeremy Gagnon-Lapare and scored on a header.Hirving Lozano then scored on a right-footed shot from just outside the penalty area in the 57th minute.
Mexico's Gibran Lajud stopped Michael Petrasso's penalty kick in the 80th minute and a follow-up shot from Jay Chapman.
Honduras earned the other automatic berth from the North and Central American and Caribbean region with a 2-0 win over the United States.
Canada will play the U.S. in the third-place game Tuesday, and the winner meets Colombia in March for another Olympic berth.
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