Nicolas Sanchez scored the only goal of the game as Monterrey edged hosts Tigres UANL 1-0 in the first leg of the CONCACAF Champions League final.
Sanchez's 43rd-minute goal gave Monterrey a slender lead following Tuesday's opener away at Estadio Universitario de Nuevo Leon in the all-Mexican decider.
Two-time runners-up Tigres – who have never won the competition – overcame Santos Laguna 5-3 in the semi-finals, while Monterrey humiliated Sporting Kansas City 10-2.
Tigres had gone nine matches unbeaten on home soil in all competitions but Monterrey snapped that run thanks to Sanchez prior to half-time.
With two minutes remaining until the interval, Argentine defender Sanchez rose highest to head past Tigres goalkeeper Nahul Guzman.
Monterrey – three-time winners with their last Champions League title coming in 2013 – will welcome Tigres to Estadio BBVA Bancomer for the second leg on May 1.