Substitute Peter Byers scored in injury time to lift the Montreal Impact to a 1-0 victory over Vancouver on Wednesday night.
The win denies the defending league champions the one point they needed to clinch a playoff berth. The Impact swept all three regular season games with the Whitecaps this season.
The 12-10-6 Impact now has five wins and a draw in their last six games. The Whitecaps dropped to 9-10-9 and ended a seven-game unbeaten run.
Byers, who had a goal called back by a quick whistle in the 81st minute, fought off three defenders inside the penalty area before slipping a left-footed inside the far post.
Only 19 minutes earlier, the crowd of 11,867 at Saputo Stadium booed when a Byers' goal was called back because referee Silviu Petrescu had whistled for a Montreal free kick just before the Impact striker fought off a hold by Chris Pozniak and shot inside the far post from 12 yards.
The crowd booed again as Montreal sweeper Nevio Pizzolitto was shown a yellow card -- which will bring a two-game suspension for accumulating eight cautions in the season -- in the 83rd minute, and again when Byers was hauled down by goalkeeper Jay Nolly to nullify a chance in the 86th.
"A huge win," said Pizzolitto. "From the first half, we played really good soccer.
"We created chances, we had a goal disallowed, but we kept pushing and Peter Byers was a machine out there."
It was Montreal's first game since a report this week that England star David Beckham may buy into the club if it moves to the more prestigious Major League Soccer in 2012.
"It's all rumours, but it would be great for the city," said Pizzolito. "But until it's confirmed, we can't talk to much about it."
Montreal, which clinched a berth in the playoffs when Rochester beat eighth-place Miami FC on Tuesday night, moved into fifth place, one point ahead of the idle Rhinos. The top seven teams make the playoffs.
