A new and unique hybrid cultivar of Phlox plant named Phlox ‘;Opening Act Ultrapink’; multi-stemmed, medium height, upright, slowly-spreading habit with clean, medium-green, glossy, lanceolate leaves with exceptional powdery mildew resistance. Foliage is thick and leathery on stiff stems. Flowers are vibrant, florescent, rose-pink, produced on branched peduncles and nearly cover the top of the plant beginning early summer, about two weeks prior typical Phlox paniculata cultivars, continuing for about five weeks and reblooming through late summer. ‘;Opening Act Ultrapink’; is especially suitable as a potted plant, for the garden, for attracting hummingbirds and butterflies, and for cut flower arrangements.