Fredy Montero sent home a free kick late in the second half and the Seattle Sounders defeated Toronto FC 1-0 on Saturday.
The Seattle striker beat Toronto goalkeeper Stefan Frei in the 90th minute into the top right corner after Reds defender Doniel Henry committed a foul just outside the penalty area.
"It's incredible we lost the game. We deserved to win. We played very well and in the end we have given it away," Toronto coach Aron Winter said. "At that moment it's not clever for us to foul in front of the box."
With Toronto up a man and pressing, Henry fouled Seattle's Mauro Rosales on a Sounders counterattack to set up Montero's winner.
"Very frustrating. I feel like we got robbed of a pretty decent performance," Frei said. "I don't like the way we gave away that foul. I don't even know if it was a foul. It's the 90th minute, the guy goes down extremely soft. Down a man they're looking for that."
Toronto (2-6-9) couldn't take advantage of Jhon Kennedy Hurtado's second yellow card and is winless in eight matches (0-3-5). The Reds haven't won in MLS play since a 2-1 defeat of Houston on May 7.
Seattle, which played Vancouver to a 2-2 draw last weekend at home, improved to 6-4-7.
"That goal was amazing," Montero said. "I was looking to score in the past four or five games and I just want to keep working hard."
The Reds came closest in the 81st minute when second-half substitute Javier Martina hammered a shot off the post before Joao Plata sent the rebound over the Seattle cage.
Hurtado was sent off in the 49th minute for a second yellow card. The Seattle defender clattered into Toronto FC forward Alen Stevanovic from behind.
Sounders goalkeeper Kasey Keller said his team played well after going down a man.
"I thought we played smart," Keller said. "We rode our luck at times. They hit the post and had some other balls bounce around our box but the guys worked hard."
Toronto couldn't capitalize on the ensuing free kick, with Danleigh Borman curling a ball in from the right that Seattle's defense handled with little trouble.
Plata used some fancy footwork to get by a Seattle defender in the 56th minute, but his cross didn't connect with any Toronto player in front of Keller.
Mike Fucito's header whizzed past Frei's post in the 59th as Seattle tried to mount some offense while down a player.
Mikael Yourassowsky was shown a yellow in the 65th, but Seattle couldn't make Toronto pay on the ensuing free kick and Frei did well to collect off the foot of an onrushing Mauro Rosales in the 75th.
Maicon Santos got on the end of a Martina cross in the 78th, but he could only head it weakly over the Seattle goal.
"It's a tough result because we deserved the win. Not just a tie, but we deserved to win," Frei said. "It's going to be tough to bounce back from this. Today would have been a perfect opportunity to maybe get something going offensively."