Christopher McVey opened the scoring in the 14th minute, and Pellegrino added another goal in stoppage time to secure the halftime lead. San Diego dominated possession with 64% and outshot Montreal 12-6.
Montreal struggled after Tomas Aviles received a straight red card in the 50th minute. Youngsters Onni Valakari, Marcus Ingvartsen, Bryan, and Zamblé made their MLS debuts, while 18-year-old Duran Ferree made his debut with two saves.