Marco Di Viao canceled out a first-half strike from Vincent Nogueira to give the visitors their first point of the season.
It was headed that direction again until Di Vaio received a Justin Mapp pass on the left wing, rushed into the penalty box and curled the ball past Union goalkeeper Zac MacMath while center back Amobi Okugo was as much of a spectator as the fans at the River End of PPL Park.
The Italian forward's 80th-minute tally made it 1-1, as Philadelphia was unable to take advantage of a Montreal team down to ten men after substitute Andrew Wenger was sent off for a studs-up tackle.
The Union had been the better team in the first half and showed it with Vincent Nogueira getting free on the right side on a number of occasions. He wasn't able to finish his earliest chance but made no mistake when he was given another opportunity in the 35th minute.
The club seemed to stall a bit in the second half and tried to get a boost by bringing on Leo Fernandes and Conor Casey. The additions saw little of the ball and weren't able to turn the tide even after Wenger's sending off, and Philadelphia was again left feeling it should've performed better, falling to 1-3-0 on the year.