Marquinhos netted the opening goal and the game-winning penalty as PSG went on to a 5-3 penalty shootout win over Roma.
The Loons and Dynamo created few chances between them, with the match ending in a testy draw between Western foes.
Sacha Kljestan scored his first goal of the season as his side manhandle San Jose 5-1.
A brilliant David Villa was cancelled out by a clumsy challenge in the box and Victor Vazquez's penalty in stoppage time.
Montreal's Swiss maestro put the team on his back against a feisty Union team, with a marauding goal sealing Montreal's win.
International Champions Cup: Alphonse Areola (65') AS Roma 1-1 PSG