The last time Millwall visited The Hawthorns, Albion secured a hard-fought 2-0 victory to record a sixth successive league home win at the time.
Despite a resilient performance from the Lions, Dwight Gayle pounced from close range to break the deadlock for the dominant Baggies in the 68th minute.
Kieran Gibbs made sure of all three points with a well-taken drilled finish into the bottom corner shortly after, with the result lifting Albion into third place in the table.
