Real Salt Lake (11-4-9) moved one point ahead of Seattle (13-7-2) with its third straight victory as it remained unbeaten in its last six matches.
"We knew we were on top of them and not to get frustrated," said defender Tony Beltran about RSL's multiple chances in a scoreless first half. "We knew the goals were going to come. We said if we came out in the first 20 minutes and took it to them, they were going to go away. That's exactly what happened."
"It doesn't get much bigger than this," said defender Nat Borchers. "To play a game for first place against one of the best teams in the league. The crowd was amazing. You could just feel the vibe coming into the stadium. The fans were pumped up and it got us amped up from the start."
After a scoreless first half, Real Salt Lake scored twice in a four-minute span at the start of the second. Plata, the shortest player in MLS, headed in a goal for a second consecutive game in the 53rd minute. Then Real Salt Lake got an own goal when Seattle's Osvaldo Alonso was battling with Luke Mulholland inside the box. Replays showed that Mulholland actually got a foot on the ball.
"Whoever is saying that's an own goal is blind," Mulholland said. "I'll fight this all the way to the courts. Cassar said to us as the second half progresses, we were going to get stronger and they'll get weaker. I think that showed."
After video sent to MLS by ABC-4, the scoring ruling was changed and Mulholland was given credit for his 6th goal of the season.
Chad Barrett scored for Seattle in the 72nd minute after a wild sequence. Clint Dempsey's close-range attempt was blocked and Andy Rose's rebound header went off the post. Barrett finally put it past goalkeeper Nick Rimando, spoiling his bid for a third straight shutout.
But RSL's defense clamped down in the final 18 minutes to preserve the win. RSL's exacts a little revenge from earlier in the year, when the Sounders won handily at home 4-0, ending RSL's season-opening 12-game unbeaten streak.
With the victory, RSL now has 41 points, one more than Seattle, although the Sounders do have two games in hand on Real.
"I think we're definitely in form right now," said midfielder Ned Grabavoy. "I think you're seeing a complete understanding of each individual and collectively as a group what everyone's roll is."