Kekuta Manneh then tested the New York keeper, who was equal to the Gambian forward's strike.
Cristian Techera had the ball in the net for the Whitecaps after 26 minutes but the midfielder's effort was ruled out for offside.
Saunders was called into action straight away in the second half, saving Kendall Watson's goal-bound header from a Rosales free kick.
Vancouver then worked the ball into the New York box but forward Darren Mattocks was unable to make a telling connection.
Manneh went close from range in the 63rd minute, as did defender Jordan Harvey ten minutes later.
However, another penalty was awarded in the dying minutes of the tie as Lampard drew a foul inside the Whitecaps box.
New York skipper Villa stepped up and duly dispatched the 95th-minute spot kick to hand his side all three points. body check tags ::