Choosing a top Rocky film isn’t easy, yet Rocky IV presents a strong argument for being number one. The climactic battle with Ivan Drago has a level of feeling, sincerity, and inspiration that surpasses what's found in the other installments. Considering the political tensions between the United States and Russia during that period only enhances the experience. Achieving the right tone for the final fight proved so important that Sylvester Stallone suggested they actually box, which resulted in him being hospitalized after a knockout by Dolph Lundgren. Ivan Drago is undeniably the series’ most compelling antagonist. The evolution of the bond between Rocky and Apollo in Rocky IV reflects superb writing and years of character development across four films. A touch of Christmas cheer adds to the film's charm. If I were limited to watching just one Rocky movie, this would be my choice; however, its quality is largely due to what it builds upon from the earlier movies.

Source on TMDB