Fafa Picault scored in the third minute of second-half stoppage time Wednesday night, and the Philadelphia Union halted Seattle's MLS-record nine-game winning streak by beating the Sounders 1-0.
Goalkeeper Stefan Frei rolled a soft clearance pass out toward defender Gustav Svensson. But Picault got to the ball an instant before Svensson did and took it into the left side of the penalty area 1-on-1 against Frei. From 8 yards away, he drilled it into the net for his eighth goal of the season.
The Union (13-12-4) won for the fifth time in six games.
The Sounders (13-10-5) lost for the first time since dropping a 3-2 decision to Portland in Seattle on June 30. In addition to the nine straight wins, they had an overall unbeaten streak of 12 games during that stretch (10-0-2), just one shy of the club record.
Philadelphia thought it had gotten on the board in the 65th minute when a long through ball from Haris Medunjanin found Cory Burke streaking up the right wing side. Burke took the ball to the right side of the 6-yard box and shot past Frei at the near post.
The Sounders were back at midfield preparing to kick off when the video review was called. After just a few seconds, referee Ismail Elfath walked away from the screen and waved off the goal, ruling that Burke had been offside.
Jim Curtin's squad takes on Sporting Kansas City on Sunday, and then will play the Houston Dynamo in the U.S. Open Cup Final next Wednesday.