A three-goal spurt in five minutes has Monterrey on the brink of the CONCACAF Champions League quarterfinals.
It can get there with a win or draw at Saprissa on Tuesday, or let Seattle do the work with Wednesday a win or draw against Marathon.
Monterrey appeared headed for their first loss in the Champions League last week when an own-goal and another by Michal Fucito had it trailing 2-0 at halftime.
But the insertion of Humberto Suazo in the second half resulted in a goal by Aldo De Nigirs in the 73rd, another by Suazo a minute later and a finale by Luis Perez in the 78th. Coach Victor Manuel Vucetich hopes the scare by Seattle provides a reminder with two games remaining in the Group Stage.
"This should serve us in order to benefit more from the first half," he said. "One factor that intervened on our favor was for us to have patience, give it time. The goals fell at the opportune time for us to be able to react."
Group C leader Monterrey also remains atop Group 1 in the Mexican Apertura, one point in front of Santos, after playing to a goalless draw at Queretaro on Saturday.
Saprissa should enter the match rested with its last match - a 2-1 loss at Marathon in the CONCACAF Champions League - a week ago. El Monstruo Morado, which is second in Group B with seven points, can book its knockout stage ticket with a win against Monterrey and a victory by Seattle against Marathon.
In the previous encounter with Santos, Saprissa fell 1-0 at Estadio Tecnologico with De Nigris scoring the lone goal in the 25th minute.
Marathon kept its hopes of advancement alive with a 2-1 win against Saprissa last week and could use some help from Monterrey against the Costa Rican side.
"I believe that we will get there with time, but the place is far away," Marathon manager Edwin Pavon said.
Marathon beat Seattle 2-1 at Estadio Olimpico Metropolitano on August 19 with goals by Orvin Paz and Nicolas Cardozo in first-half stoppage time.
El Monstruo Verde will face a Seattle squad all but mathematically eliminated from advancing to the knockout stage. The Sounders FC, though, are very much alive in the MLS Cup playoff race and won 1-0 at Chicago Fire at Toyota Park Saturday night.
Blaise Nkufo scored the lone goal for Seattle, which has 39 points from 26 matches and is tied with the San Jose Earthquakes for fourth place in the Western Conference.
"Tonight was one of those games where you pull up your sleeves and just battle and fight," Seattle coach Sigi Schmid said after the club's fourth match in 13 days. "We knew Chicago was going to come out with great intensity, but for them it was a playoff game. We had to make sure we matched their effort and I thought we did a good job of that."