09/23/2013 06:54 EDT | Updated 11/23/2013 05:12 EST

Impact need big offensive performance against CD Heredia to stay alive

MONTREAL - The Montreal Impact's chances of staying alive in the CONCACAF Champions League consist of a sliver of hope.

Montreal will not only have to beat CD Heredia in their final group stage game Tuesday night at Saputo Stadium, they will have to outscore the Guatemalan side by a wide margin to have any chance of staying alive, much less advancing to the championship round.

"We'll have to make the nets bigger on Tuesday," Impact head coach Marco Schallibaum joked after Montreal's 3-0 Major League Soccer loss to Vancouver on Saturday night.

Big enough for Montreal to win by six goals. That is the goal-differential they will have to overcome if the group stage ends in a three-way tie, which is the only scenario that remains in which the Impact can go through.

Montreal came up with a 6-0 win over Toronto FC in the first round of the Amway Canadian Championship to advance to the final, where they beat out the Whitecaps to claim the Voyageurs Cup.

"We'll go into the game knowing we have to win and that we'll have to push to give ourselves every opportunity to advance from the group, knowing that we did everything we could on the field," midfielder Patrice Bernier said after practice Monday.

The Impact have dropped their last two MLS games at Saputo Stadium. Prior to that, they were 9-1-3 at home in league play, including a 5-3 win over Philadelphia on May 25 and a 5-0 drubbing of Houston in their last home win on Aug. 24.

Montreal forward Andrew Wenger feels the team can draw on its previous high-scoring results to keep its hopes alive.

"It gives us confidence that what some might think is impossible is possible," Wenger said.

CD Heredia currently leads three-team Group 5 by virtue of home wins over the Impact and the San Jose Earthquakes. They would advance to with a win or a draw in Montreal, or at least a point in the final group stage game.

Schallibaum said after Monday's practice that he would be resting some players Tuesday, though he would not say who.

"They know that the message is clear," Schallibaum said. "We have to win this game to keep going. We have a small chance so we're all going to try to take that opportunity. That's how we're going to approach it."

An Impact win Tuesday night would make CD Heredia's game next month in San Jose the decisive one.

If Montreal were to win, the Earthquakes could bring about a three-way tie with a win over CD Heredia on Oct. 23.

That scenario would eliminate the Guatemalans, whose home wins were both by the score of 1-0, by virtue of goal-differential.

And that is precisely what has put the Impact behind the 8-ball.

While Montreal and San Jose each prevailed in their home games against each other, the Earthquakes gained a huge goal-differential advantage with a 3-0 win over the Impact last Tuesday after opening the group stage with a 1-0 loss at Saputo Stadium on Aug. 7.

"We're going to take the pitch motivated to play well and have a strong start," defender Hassoun Camara said. "After that, we have the kind of group that can score a goal or two quickly so we'll see how it goes."

Montreal, which is 13-9-6 in its sophomore MLS season, is currently third in the Eastern Conference with 45 points in 28 games. The Impact, who play four of their last six on the road, are in Chicago on Saturday.

"We realize that the last week wasn't very positive in terms of points," said Bernier, who turned 34 on Monday. "There's no crisis but we've got six games left, seven including Tuesday, so we've got to get back to basics in order to get back on track so that when we reach our objective everyone on the team, not just the starting 11, can make a difference, whether it's playing for 10 minutes or 90 minutes."