TFC, winless in league play, may see Wednesday's matchup as a chance to turn its season around.
''It's a dangerous time to play them,'' Montreal coach Jesse Marsch said this week. ''There's obviously some desperation there.
''In this tournament, it's a fresh start for them and I'm sure that's what they're looking at. You can almost throw a lot of results out the window because now you're playing in a derby match, a cup game. We have to be ready for a hard-fought, emotional game.''
The two clubs meet in the first leg of the semifinals at Olympic Stadium, where TFC begins its bid for a fourth straight title. The Vancouver Whitecaps meet NASL club FC Edmonton in the other semifinal.
The Reds are 0-7-0 in MLS action this season, surrendering a league-worst 16 goals, while the expansion Impact is 2-5-2 and is unbeaten (2-0-1) on home turf.
The return leg of the two-game, aggregate goals series is a week later in Toronto.
Toronto coach Aron Winter will have his team up for Wednesday's game. He was unhappy at the lack of intensity his side showed in an earlier league loss this season in Montreal.
Despite his team's record, he is not backing down.
"I think that Montreal, the team, is not playing at this moment so well and that we can get a good result (Wednesday)," he said.
"We are preparing ourselves because it is also a derby. We have to again work hard together, stay together and try to get the good result."
The Canadian Championship winner not only takes home the Voyageurs Cup but earns a berth in CONCACAF Champions League play. The promise of making a mark in international play has made it a priority for the Impact.
Sporting director Nick De Santis even addressed the players this week on the importance of the competition to a club made up mostly of new arrivals from the U.S. and Europe
De Santis recalled 2009, when Montreal surprised many by reaching the Champions League quarter-finals. They drew more than 55,000 to Olympic Stadium for a 2-0 victory, but then collapsed in the second half of the second leg of an embarrassing loss to Santos Laguna in Mexico.
Toronto went one better in the 2011-12 Champions League, knocking off the LA Galaxy in the quarter-finals in March to become the first Canadian club to reach the semifinals.
But they suffered the same fate as Montreal two years earlier. They beat Santos Laguna in the opening leg at home, then were drilled for four second-half goals in the return match on April 4 for a 7-3 aggregate loss.
''We talked a bit before practice about how important these games are,'' said forward Eduardo Sebrango, a key member of the 2009 Impact and one of the few who made the jump with the team to MLS. ''We experienced what it's like in CONCACAF and we want to do that again.
''We'll take these games seriously. It's huge for us. And obviously Toronto's in a bad spot so it's going to be a huge game for them as well.''
TFC has at least got its attack on track in recent matches but defence continues to be a trouble spot. On the weekend, they battled evenly with a top club, Real Salt Lake, only to give up a late goal for the 3-2 loss.
Their record includes a 2-1 setback at Olympic Stadium on April 7, the Impact's first MLS victory. Montreal is coming off a 2-0 win at home over Portland.
Both clubs will also have in mind key league matches on the weekend. TFC will be at home to Dwayne De Rosario and D.C. United on Saturday, while the Impact travel to first-place Sporting Kansas City.
But 39-year-old Sebrango said nothing matches the emotion of a cup series, particularly against a rival.
''They are more intense because it's only two games,'' the Cuban-born striker said. ''They're almost like playoff games. It's a short series and, if you're not ready, you'll be out of the competition in a week.
''Obviously our fans hate Toronto and the Toronto fans hate us. I expect some fans from Toronto to make the trip. It will be fun to be involved.''
Montreal is expected to make few changes with Jeb Brovsky expected to fill in at right back for Zarek Valentin, who suffered a bruised calf against Portland.
Left side midfielder Justin Mapp rode a bike on the sidelines during practice this week. If he is unable to play, Sinisa Ubiparipovic could start.
For Toronto, Nick Soolsma (hamstring) is not yet ready while fellow forward Danny Koevermans (groin) is also doubtful.