Real Salt Lake maintained its three-point lead over Seattle by drawing 0-0 away to the Sounders on Wednesday, with the hosts hanging on despite being a man down for the final hour.
The result moved Salt Lake to 56 points compared to Seattle's 53, though the Sounders have two games to play compared to Real's one. Both teams have already qualified for the playoffs but the order of their finish affects seedings and home-ground advantage.
Seattle was reduced to ten men when defender Zach Scott was issued a second yellow card and sent off in the 30th minute after a reckless tackle on midfielder Javier Morales.
There were very few scoring chances in the match, but Seattle's Austrian goalkeeper Michael Gspurning saved the draw for the Sounders in the final moments. He first punched Chris Schuler's shot wide of the goal then, after a scramble in the box, he kept Sebastian Velasquez's deflected shot out of the net.
Seattle hosts Dallas on Sunday then closes the regular season on Oct. 28 at Los Angeles.
Salt Lake closes its season on Oct. 27 hosting Vancouver. If the sides finish level on points, the first tiebreaker in playoff seeding is total goals scored where Seattle holds a slight advantage.
The Sounders are also closely looking behind at the Galaxy, who are only three points behind with two games left.
