Zlatan's movement was undoubtedly good, but was not relying on speed. He would usually be close to a defender then give him a nudge before moving in the other direction.As stated above. Zlatan made this type of run last year. He still would do when we are so obviously in transition.
I rarely recall Zlatan making a run with speed on the counter. He might have attempted that run Lukaku made for the 1st goal, but he never would have made it to the ball.