Edgar Benitez and Paul Nicholas Aguilar scored for Pachuca as it posted a 2-0 victory over Houston, which played the second half a man down following a second caution issued to forward Dominic Oduro in first-half stoppage time.
Of the 18 matches MLS teams have played against Mexican clubs south of the border, there is only a 4-4 tie earned by Houston against UNAM in the Concacaf Champions League nearly a year ago. MLS teams have been outscored, 60-14, in Mexico.
Houston didn't start eight starters from its 2-1 loss at Columbus on Sunday. They include recent Mexican signing Juan Angel Landin, who is cup-tied. U.S. international Jose Francisco Torres started for Pachuca.
Pachuca applied pressure from the kickoff and after twice threatening the Dynamo goal, Benitez scored in the 26th minute. He ran onto a long ball and outpaced the Dynamo defense long enough to shoot past keeper Tally Hall from just inside the penalty area. Hall foiled Benitez later in the half by using his arm to block a shot and then snuffed Juan Carlos Chaco's follow-up attempt.
Shortly before the goal, Oduro had been cautioned, and when he tackled playmaker Christian Gimenez from behind in the final minute of the first half, referee Elmer Bonilla pulled out the yellow card and then the red.
Aguilar added an insurance goal in the 74th minute to highlight a second half dominated by the host. Gimenez played him a pass and Aguilar evaded tacklers at the edge of the penalty area to hit a shot that took a deflection and skipped past Hall.
Houston, which sits in third place with four points from three games, hosts group leader Arabe Unido of Panama (seven points) next Tuesday at Robertson Stadium. Pachuca, in second with six points, next plays pointless and goalless Isidro Metapan in El Salvador.
Sept. 16 in Pachuca
Pachuca 2 Houston Dynamo 0. Goals: Benitez 26, Aguilar 74.
Pachuca - Calero, Perez, Aguilar, Munoz, Torres, Correa, Gimenez, J.Torres (Alvarez, 77), Manso (Montes, 68), Cacho (Caballero, 68), Benitez.
Houston - Hall, Barrett, Cochrane, Boswell, Waibel, Davis (Chabala, 74), Hayden, Ustruck (Mullan, 64), Cameron, Ching (Weaver, 46), Oduro.
Red card: Oduro 45.
Referee: Elmer Bonilla (El Salvador).