Millwall were under the cosh for long periods of the game but Steve Morison's late winner ensured the Lions will compete in the Championship next season.
Excitement among the south Londoners' supporters spilled over onto the playing surface, with large numbers of fans rushing onto the pitch as the atmosphere threatened to turn nasty.
Many fans opted to make their way into Bradford's half, goading manager Stuart McCall and his crestfallen players.
Supporters taunted their Bradford counterparts before stewards intervened and implemented a barrier on the halfway line to minimise confrontation.
But McCall claimed he considered resorting to physical violence in response to the provocation.
Millwall have a history of pitch invasions and were subject of an FA investigation as recently as February after their fans invaded the New Den after an FA Cup victory over Leicester.
Watch the video at the top of the article to see the Wembley pitch invasion....
