Santos Laguna, fresh off a Liga MX win over Monterrey, couldn't break down Rayados in the CCL final first leg at home.
Cesar Delgado was sent off in the goalless draw.
Both goalkeepers had to make saves in the opening minutes, Oswaldo Sanchez on a quick Humberto Suarez turn and Jonathan Orozco kicking away Oribe Peralta's drive.
A bright start bled into some chippy tackles, with the referee handing out five yellow cards in the opening 25 minutes.
Early in the second half, Humberto Suazo struck the post.
Minutes later, Peralta took a tumble in the opposition box. He was whistled for a foul, but he picked up an injury in the sequence. Herculez Gomez replaced him.
The American quickly made an impact. Cesar Delgado rushed into a tackle late, catching Gomez after the ball was gone. The referee ejected Delgado, reducing Monterrey to 10 men with 25 minutes remaining. Coach Víctor Manuel Vucetich responded by withdrawing Jesus Corona for Gerardo Moreno.
The ploy worked, and Rayados succeeded in sucking the sting from the match, slowing play and preventing Santos from scoring a home goal. The final returns to the Estadio Tecnológico next Wednesday.
Follow ZAC LEE RIGG on or shoot him an email