The Union could have strengthened their playoff position, but a late goal from Montreal left them with another tie that certainly felt like a loss.
Matteo Mancosu's bouncing header at the far post in the 88th minute was the equalizer as the Impact played the Union to a 1-1 draw on Saturday night before 18,500 at Talen Energy Stadium.
The Union (11-10-8) remain in fourth place in the Eastern Conference with 41 points. Montreal, right behind, is now 9-8-11 for 38 points. The top six teams in the conference will make the playoffs.
"It's never easy, especially when you feel you are going to get three points," said defender Keegan Rosenberry, who had great success attacking out of the back.
Montreal had a different feeling on the tie.
"We're down one and come back late, so in the end it was a good result for us to come back," Impact coach Mauro Biello said.
The tying goal came off a corner kick, which two other Impact players touched before Mancosu, standing at the far post, got inside of Union midfielder Warren Creavalle, and headed the ball in.
"It was difficult to give up a restart goal and I am disappointed from that standpoint, but there were still a lot of strong performances from our guys," Union coach Jim Curtin said. "We just couldn't get that second goal in the second half."
The Union have five games left, with the next three on the road. So failing to earn three points could prove crucial.
For the longest time, it appeared as if Tranquillo Barnetta's impressive goal would stand up.
In the 45th minute, Barnetta took a pass from Fabian Herbers and turned on the jets. He dribbled through two players and then blasted a shot from 25 yards out just inside the near post for his fifth goal of the season.
"I saw two defenders, I decided early to try to pass them and shoot and it was right in the corner," Barnetta said.
Union keeper Andre Blake made two big saves, one in each half on Mancosu, showing his quickness coming off his line.
After losing to Orlando City, 4-1 on Wednesday, the Impact didn't start standout forward Didier Drogba and inserted him in the 61st minute.
Both before and after that, the Union showed a strong attack.
Curtin, along with the Talen Energy Stadium crowd, thought that Herbers should have been awarded a penalty kick in the 59th minute when he was taken down in the box.
There were other chances.
In the 77th minute, Ilsinho sent a shot from inside the box over Impact keeper Eric Kronberg that just went wide.
Kronberg, who appeared in just three games last season, was playing his first MLS game this season, replacing Evan Bush, who received a red card in the loss Wednesday.
"We had to close the game earlier and needed a second goal," Barnetta said. "We had really good chances."