Alvaro Saborio hit a double and Javier Morales assisted two as RSL took a commanding 3-0 first leg lead over Seattle in the playoffs.
Seattle, yet to win a playoff match, didn't muster a shot on goal and now must overturn a three-goal deficit in the second leg on Wednesday if it is to advance.
"We're lucky we didn’t lose 6-0. We were well-served by losing only 3-0," Sounders coach Sigi Schmid said. "We played not well and I thought Real Salt Lake played very well. Hats off to them."
A scrappy opening half saw RSL take the majority of possession but struggle to carve out exceptional chances. However, with Seattle failing to test Nick Rimando, the first goal always looked likely to come from the hosts.
"One of our focuses was to keep a zero back there," Rimando said. "We knew they had some lethal weapons up top and in the midfield and (we had) to stay compact. All in all I think my job was pretty easy tonight because of the guys in front of me keeping it tight, keeping a high line and stepping to the ball."
When the goal did come, it carried controversy with it. Javier Morales laid the ball off to Chris Wingert in the box. The fullback's shot squirmed past Kasey Keller and was heading in when Saborio poked it home. The Costa Rican might have been a few inches offside, if at all, but the goal stood.
There was no doubt about the second. Morales again assisted, crossing from the right touchline. Saborio finished with an audacious backheel, reaching his leg around the defender and flicking the ball into the far corner of the net.
The occasion started to get the better of Seattle, the reigning U.S. Open Cup champ. Twice Leo Gonzalez leveled RSL players when the referee wasn't looking, and shortly after the second goal Osvaldo Alonso pushed Saborio over off the ball. The Cuban midfielder's hands were at face height, and he should have been ejected, but referee Mark Geiger could only locate his yellow card at the moment.
The Sounders' best chance came when a deflected Alvaro Fernandez cross bounced off the top of the crossbeam.
In the late going, the 17,067 in Rio Tinto Stadium got the sledgehammer third goal which should make the second leg a formality. Andy Williams' cross was batted away from goal. Substitute Ned Grabavoy out-hustled Gonzalez to it, and slammed a shot on frame. Keller, who made eight rather impressive saves, could only paw at the ball, with the pace taking the shot in.
"We just had to come out better than we did. Those are not goals we want to give up," Seattle forward Mike Fucito said. "We created some chances, we just couldn’t put them away. Everything from top to bottom can be better. They were more physical; we just need to be tougher all around."
The main concern for RSL was that both central defenders, Jamison Olave (right quad strain) and Nat Borchers (left knee strain), limped off and are doubts heading into the second leg on Wednesday in CenturyLink Field.
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