After losing their regular season finale in Toronto on Saturday, the Impact could only sit and watch as other teams decided their playoff fate.
Finally, a 5-2 win by the New York Red Bulls over the Chicago Fire gave them fifth place and the final Eastern Conference post-season berth.
Montreal (14-13-7) will face the fourth-place Dynamo (14-11-9) in Houston on Thursday night in a one-game playoff.
"In the end, we're still alive. That's very positive," coach Marco Schallibaum said Monday. "We were on life support.
"We were very frustrated on Saturday. But we're still alive and we have another chance."
If the Impact win, they will play host to the first-place Red Bulls in the first leg of their semifinal at Saputo Stadium on Sunday, with the second leg later in the week in New York.
It was a shocking way to end the season for Montreal, which dominated the first four months while building a 9-3-2 record but went flat with a 5-10-5 record after that. They were 1-6-1 in their final eight games.
Even Impact defender Matteo Ferrari wonders if they deserved to make it.
"I was sure that New York was going to win the game but still, even if they won, we don't merit (it)," the Italian centreback said. "I want to be honest because everyone knows, we don't merit right now.
"We merit before, for sure, because we played almost perfect at the beginning of the season. Now we have to get back to where we were."
Captain Davy Arnaud was having none of that.
He was hosting his daughter's birthday party on Sunday, but couldn't resist putting MLS games on the television to see what his team's fate would be. Depending on the results, they could have ended the day anywhere from third to sixth place.
He said that even if the team played badly down the stretch, they did enough to continue for at least another day.
"We got into the playoffs off our performance over a 34-game season," he said. "Our form hasn't been the best of late and our results at the end of the season weren't what we wanted, but everyone plays 34 games and you finish where you deserve, regardless of what other people do.
"We needed some help after our result in Toronto, but I look at what we've done (all season)."
The club made progress by reaching the playoffs in only its second season in MLS. They finished seventh with a 12-16-6 record as an expansion team in 2012.
They also won the Amway Canadian Championship and set a record for a Canadian MLS club with 49 points.
If they beat Houston, the Impact will be the first Canadian team to reach a conference semifinal. Vancouver was beaten in a playoff knockout game last year.
"It's a big step," said Arnaud. "We should be proud of the fact that, in the second season of this group being together, we got into the playoffs because it's not easy.
"To be honest, with the way we started the season, we were a little disappointed that we're finishing fifth because we know we can be a good team. But we still have a chance to be playing on the last day, and that's important."
They should have some help against Houston.
While centreback Alessandro Nesta won't be able to return from a calf injury, midfielder Patrice Bernier said he will be back from a hip injury and Schallibaum said central defender Nelson Rivas, who hasn't played this season due to chronic bad knees, should be able to play at least the final 20 minutes.
Left back Jeb Brovsky, who has been out two weeks with a broken toe, is back training at full speed as well.
Montreal beat the Dynamo twice at home this season by 2-0 and 5-0, but lost 1-0 in Houston on Oct. 4. They are 0-2-1 in Houston over two seasons.
The Dynamo are tough at home. The orange-clad side led by Giles Barnes and Will Bruin reached the final last season.
"They're very good and experienced," said Arnaud. "They had to win on the last day to get in, but if there's one team in the league that knows how to get the job done in the playoffs it's Houston.
"They find a way to step up and play at a different level and we have to be prepared for that."
Houston may not want any part of the Red Bulls. New York went 3-0 against the Dynamo and outscored them 9-1 this season.
Montreal beat the Red Bulls at home 1-0 early in the season, then lost by 2-1 and 4-0 in New York. They haven't met since July 13.
The Seattle Sounders play host to the Colorado Rapids in a Western Conference playoff game on Thursday, with the winner advancing to a semifinal against the Portland Timbers.