Montreal blew an opportunity to clinch a playoff berth at BMO Field, and must now wait a day to learn its fate.
Robert Earnshaw's 16th-minute goal made the difference, and the Impact must now wait until Sunday to learn their playoff fate.
The home side took the lead following a sloppy giveaway from Montreal in the back. Bright Dike found Jonathan Osorio in the box and the young Canadian's shot deflected off Earnshaw and in, with the Welshman claiming the goal.
From there out, the home side's defense, led by goalkeeper Joe Bendik, made the lead stand up. Most notably, Bendik produced a heroic save on Andres Romero with just minutes to play to preserve the clean sheet.
With the loss by the Impact, Chicago, New England and Houston can all clinch playoff berths with wins in their respective games Sunday, which would eliminate Montreal. If New England or Houston do not win, then the Impact will clinch a playoff berth.