A ninth-minute goal from Rogelio Funes Mori was enough to settle the game for Monterrey, who were playing at home. The Argentina-born Mexico international scored from close range following an error from America defender Sebastian Caceres.
There was some doubt as to whether Funes Mori was in an offside position when Jesus Gallardo crossed the ball into the area, but a VAR review adjudged Funes Mori to be onside following Caceres' attempted clearance.
America almost equalized deep into stoppage time but for a VAR review. Monterrey forward Maxi Meza appeared to handle the ball in his own penalty area following a rebound off the crossbar but the referee ended the game after checking the incident on the monitor.
It was a fifth title for Monterrey, after previously winning in 2011, 2012, 2013 and 2019, earning them a spot in the Club World Cup.