Jose Francisco Torres and Tigres got a leg up on Seattle, while in Texas Herculez Gomez and Santos dropped a close encounter with MLS Cup bridesmaids Houston.
Houston Dynamo 1 - 0 Santos Laguna
Brad Davis and the Houston Dynamo took the lead late in their Champions League quarterfinal over Santos Laguna at BBVA Compass Stadium, giving the MLS team the series advantage.
The first opportunity for Houston came in the 18th minute when Oscar Boniek Garcia's corner kick was headed by Bobby Boswell, though unluckily for the Dynamo the ball hit teammate Warren Creavalle instead of the back of the net.
Just a minute later Santos should have gone up a goal, as Dynamo 'keeper Tally Hall miskicked his clearance, gifting the ball to Herculez Gomez. The American forward found a streaking Darwin Quintero who sent the ball over the bar and into the crowd.
The Orange brought in Davis at the half in place of Creavalle, in hopes of adding a spark to the home team.
Sure enough, in the 89th minute Davis and Corey Ashe combined in the final third to give Davis space inside the box. Davis then sent in a low, left-footed shot passed Oswaldo Sanchez to give the Dynamo the first leg lead.
Gomez was subbed out in the 72nd minute.
The series decider will take place next Wednesday in Torreon, Mexico.
Tigres 1 - 0 Seattle Sounders
Seattle escaped the first leg of the CONCACAF Champions League quarterfinals against Tigres with only a slight margin to make up.
Sounders head coach Sigi Schmidt hinted during the week that Seattle intended to be defensive on the road, and the first moments of the game gave credence to his words.
Tigres exploded out to dominate possession, and in the third minute it looked like things were about to fall apart for the visitors. Lucas Lobos found himself one-on-one against Seattle goalkeeper Michael Gspurning, but a poor shot on goal mixed with quick thinking from Leo Gonzalez and Djimi Traore kept the ball out of the net.
Managing to get into the locker room level at zero was good news for Schmidt and company, but their joy wouldn't carry over until their next locker room trip.
The hosts picked up their pace through the beginning of the second half. Seattle held back the Liga MX leaders, but in the 74th minute a mistake by veteran Zach Scott kept both Alberto Acosta and Alan Pulido onside behind the rest of the Sounders defense. Gspurning made a difficult save on Acosta's initial header but Pulido cleaned up the loose ball with defenders motionless with their hands raised.
Rather than bunkering down entirely, Seattle began to push for an equalizer and almost found one through Lamar Neagle.
Mario Martinez sent in a cross from the left wing towards Neagle's feet. The speedster managed to get a foot to the ball, but Tigres goalie Enrique Palos laid out for the save with relative ease.
American international Jose Francisco Torres played the full 90 minutes for Tigres, as did USMNT teammates Eddie Johnson and Brad Evans for Seattle.
Jonathan Bornstein did not make an appearance in the available 18 for Tigres.
Marc Burch, Ossie Alonso, Neagle and Traore all saw their first competitive minutes on the field for Seattle in 2013.
Of note, Seattle's first team squad has been kept scoreless since Martinez's late goal against New York in the preseason some 282 minutes.
Seattle is off over the weekend before hosting the complimentary leg on Tuesday, while Tigres will travel to San Luis before heading north to the US.