Seattle poured 26 shots at RSL, but could only score two of the necessary three goals. Real advances to the conference final with a 3-2 aggregate win.
"It's over," Keller said. "It's been a helluva three years."
Osvaldo Alonso and Lamar Neagle scored early in the second half as Seattle racketed up 26 shots. Though the Sounders won the second leg 2-0, it wasn't enough, and RSL advances to the Western Conference Final to face either the LA Galaxy or the New York Red Bulls.
CenturyLink Field's ragged turf and a downpour conspired for a soggy slog of a first half. Both teams struggled to connect plays and the desperation of Seattle to score early showed.
Alvaro Fernandez and Brad Evans went down injured in the first 20 minutes and had to be replaced for the home side.
Seattle worried the fates weren't aligned a little over half an hour into the match. Nick Rimando punched the ball out of the box, only for Jeff Parke to volley straight back at the unmanned goal. Tony Beltran, moving past the shot, somehow managed to contort his body back and head the ball away from danger.
"I'm not really sure what happened, it happened so fast," Beltran said.
Beltran was hurried back from injury when neither starting center back Jamison Olave or Nat Borchers (quad strains) made the 18. Chris Wingert slid into the middle to partner Chris Schuler.
A few minutes later, the Sounders put the ball in the back of the net. Fredy Montero hip-checked Rimando when going for a loose ball and tucked a shot into the empty net, but referee Jair Marrufo whistled for the foul.
Seattle finished the half with 15 shots, 10 corners, 10 free kicks and 12 open field crosses but still no goals.
Sounders FC finally clawed one back 10 minutes into the second half. Beltran was booked for a tug on Mike Fucito's jersey in the box, and Alonso slammed the penalty kick straight down the middle. Rimando was also cautioned for refusing to give the ball to Erik Friberg after the goal.
"Alonso stepped up and buried one down the middle and they ended up getting another one and it became a game," Rimando said. "I think that's what the fans wanted and they got it."
Salt Lake struggled to string passes together, let alone attempt a foray into the Sounders half, and the second goal came on the hour mark. Montero, with the option to shoot from distance, cut the ball sharply to his left where Neagle, a first-half substitute for Fernandez, was unmarked. Neagle opened up his body and tucked a shot into the far corner of the goal despite a narrow angle.
Fabian Espindola put RSL's first shot on goal with 10 minutes left in the game, sprinting down the left channel on the counter and firing a shot on frame. Keller was still very much alert, and the 41-year-old pushed the shot around for a corner. Seattle coach Sigi Schmid chewed his scarf nervously.
However, Seattle's frantic pace and lack of composure in the final third eventually told. RSL coach Jason Kreis exhaled a huge sigh of relief as the final whistle blew, meaning his side had somehow weathered Seattle's storm.
"It's definitely a kick in the balls," Jeff Parke said.
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