A power assist unit (70) to rotate the twist knob (50) of a typical manual can opener (20) includes a coupling head (72) that is rotated or powered by a hand-held power unit (74). The coupling head includes an elongated crossbar (76) connected at its center to a torque shaft (78) that projects outwardly from the head portion (80) of the power unit. Parallel engagement pins (82) project from the crossbar (76) to bear against opposite sides of the twist knob (50) for rotation of the twist knob.