Charlie Austin has scored with his first shot on target for both West Brom and previous club Southampton
Millwall fought back from behind to knock Championship rivals West Bromwich Albion out of the Carabao Cup.
Deadline day signing Charlie Austin took just nine minutes of his debut to score his first Baggies goal, heading in from close range after Luke Steele pushed Grady Diangana's shot on to the bar.
Millwall levelled when Tom Bradshaw headed in Jiri Skalak's left-wing free-kick.
West Brom thought they were back in front when Semi Ajayi headed home Chris Brunt's corner but saw it ruled out for a foul.
At the other end, Millwall were denied when Jonathan Bond produced a fine double save from Jason McCarthy and Aiden O'Brien, before Jon Dadi Bovarsson headed over from Murray Wallace's pass.
But the Lions, who came back to draw 1-1 at The Hawthorns in the Championship on Saturday, did finally take the lead early in the second half when O'Brien scrambled the ball home from a corner.
Albion sought an equaliser but saw strikes from Diangana and Romaine Swayers fly over, while Ajayi fired into the side netting late on.
The Lions will travel to Oxford United of League One in the second round.
