Michael Arroyo got the goal for Atlante after a swift counter-attack just before halftime.
By Tom Marshall: @mexicoworldcup
Related articles Mexico secures rare win in El Salvador Mexico in underwhelming win over Guyana Bueno named San Luis coach
New coach Miguel Herrera handed debuts to goalkeeper Moises Muñoz and forward Hobbit Bermúdez and early signs suggest the changes are starting to pay off.
Pumas got off to a poor start to the season after they lost 1-0 against a San Luis team reduced to 10 men for an hour of the contest,Dwight Freeney Colts Jersey. A rocket of a shot by Jehu Chiapas from just outside the penalty area gave San Luis the points.
While Chivas finished first in the general table last season and have kept the same aqud for this season, América came in 17th position,Jordy Nelson Jersey, provoking a major overhaul of the Mexico City club in the offseason.
Ecuadorian Christian Benítez missed a first half penalty but made up for it in the second half when he opened the scoring for América. Juan Carlos Medina got América´s second in injury time.
In the relegation battle,LaMarr Woodley Youth Jersey, Estudiantes Tecos were the big losers of the weekend after they lost 3-1 at Toluca. Relegation rivals Atlas managed to tie 0-0 with Puebla despite being down to 10 men for all of the second half, while Tijuana also got a point after drawing 1-1 with Morelia on Friday,Erik Walden Jersey.
Other results: Cruz Azul 1-1 Tigres,Vernon Davis 49ers Jersey, Monterrey 2-1 Jaguares, Santos 0-0 Pachuca
Playing in front of a sparsely populated Estadio Omnilife, Chivas could do nothing to stop Atlante,Jason Pierre-Paul Giants Jersey, not one of the favorites in this year´s tournament, producing a classic smash and grab performance.
Mexico´s two biggest clubs had contrasting weekends in the first round of the Mexican Clausura 2012 championship, with Chivas losing 1-0 at home to Atlante and the new-look América winning 2-0 away against Querétaro.