The former Chelsea man came on in the 69th minute of the match at Yankee Stadium, entering the centre of midfield, but he could not prevent defeat as two Ignacio Piatti goals helped Montreal to an away victory.
The match also marked Andrea Pirlo's first MLS start, as the Italian went the full match after making his league debut off the bench against Orlando City last weekend. It was the first time that NYCFC had all three of its designated players – Lampard, Pirlo and David Villa – on the pitch at the same time.
NYCFC announced Lampard's signing in July 2014 but his loan with Manchester City was controversially extended through the end of the 2014-15 Premier League season. After joining up with his new team last month, Lampard then missed multiple games with a calf injury.
The Impact, meanwhile, announced the signing of former Chelsea star Didier Drogba earlier this week.
