Lodeiro’s winner came on a penalty kick in the 39th minute to seal the win for the Sounders (10-11-2).
Dallas (9-7-8) outshot the Sounders 15-11, with three shots on goal to four for the Sounders.
Frei had his fourth shutout of the season for the Sounders. Maarten Paes saved three of the four shots he faced for Dallas.
Both teams next play Saturday, with the Sounders visiting Atlanta United while Dallas visits the Portland Timbers.
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