What 1980's movie was the first to have an official montage?

I think you'd be hard pressed to find any evidence of a cliche 80s montage earlier than the one from Rocky in 1976.

Obviously the idea of a montage wasn't new, nor even the idea of a training montage, but Rocky did combine those two elements with cheesy inspirational synth music, and that precise style was imitated in underdog action films ad nauseum through the 80s.