Real Salt Lake's first opportunity came in the sixth minute, when Javier Morales dodged two defenders and was tripped from behind on the edge of the penalty area.
Morales' free kick was blocked, however, and his ensuring corner kick was headed out of danger by the defense.
In the 10th minute, RSL striker Alvaro Saborio's perfect pass gave midfielder Ned Grabavoy a chance from a tough angle.
Grabavoy struck his shot solidly, but Seattle keeper Michael Gspurning smothered it to prevent RSL from breaking into the lead.
Real Salt Lake had another chance in the 19th minute when Paulo Jr. split defenders and got a foot on a crossing pass.
His redirection, however, sailed just wide of Gspurning's far post.
Seattle converted an RSL turnover in the midfield into a splendid opportunity in the 30th minute.
After referee Chris Penso award the Sounders a free kick from 30 yards in front of Rimando, Martinez hit the crossbar.
But the ball bounced away, keeping the game scoreless.
In the second half, it took Seattle less than a minute to leave the partisan crowd of 19,657 gasping.
Finding himself alone at the top of the penalty area, midfielder Brad Evans had time to set himself and launch a low rocket at the goal.
As he did throughout Game 1 of the series, however, Rimando saved RSL. He dove to his left and deflected Evans' shot just beyond the near post.
When Real Salt Lake routinely cleared the resulting corner kick, the danger passed.
In the 62nd minute, Morales' harmless-looking free kick from distance nearly found the back of the goal.
With the strong wind at his back, Morales lofted the ball toward a mass of players in front of Gspurning.
Nobody touched it, though, and the Seattle keeper needed a quick response to stop what turned into a threatening shot by Morales.
After Martinez scored, Real Salt Lake swarmed around Gspurning in the final five minutes of regulation and five minutes of stoppage time, but RSL could not force overtime.