Super sub Ruidiaz came off the bench and scored a delightful game-winning goal just past the hour-mark as the Sounders downed Dallas 1-0 in MLS.
The Sounders were winless in 10 consecutive visits to Dallas (D3 L7, including play-offs) dating back to 2014 – their second-longest winless away run against a single opponent in MLS (11 straight at LA Galaxy from 2010 to 2015).
But Seattle snapped that skid thanks to Ruidiaz as Sporting KC's 1-1 draw with Portland Timbers allowed the Sounders to move top of the west by one point.
Atlanta extended its winning streak to three matches after Ezequiel Barco's first-half goal secured a 1-0 win at home to Toronto.
Since the sacking of coach Gabriel Heinze after a falling out with star Josef Martinez, Atlanta – which had won successive matches for the first time since the opening two games of the 2020 season entering the fixture – has steadily climbed the table.
Atlanta is three points outside of the play-off positions in the Eastern Conference, which is topped by New England Revolution – 3-2 victor against DC United despite ending the contest with 10 men.
Elsewhere, Rodolfo Pizarro's stoppage-time winner guided Inter Miami to a dramatic 3-2 win against Chicago Fire midweek.
Pizarro struck in the 93rd minute to clinch a third straight home triumph for David Beckham's Inter Miami, who have now lost just once in their last six games.
Philadelphia Union and New York Red Bulls were 1-0 winners over New York City and Columbus Crew respectively, Vancouver Whitecaps topped Austin 2-1, Real Salt Lake defeated Houston Dynamo by the same scoreline, 10-man Montreal drew 0-0 with Cincinnati, while Nashville and Orlando City played out a 1-1 draw.