MILLWALL boss Kenny Jackett believes his side's come-from-behind win at Southampton can help transform the Lions' league form.
Substitute Liam Feeney struck deep into injury time to bag the winner as the South Londoners recovered from a 2-1 deficit to emerge 3-2 victors at St. Mary's in their fourth-round FA Cup replay.
And Jackett has called on his side to replicate their cup heroics when Derby travel to The Den on Saturday for a crucial Championship clash.
"We didn't get the rub of the green against West Ham but the players can take some confidence from the way that we've just played against the top two sides in the division," he said.
"[It was] an excellent game tonight, we've played our part, scored three terrific goals and we really do hope that we can take this type of confidence into the league.
"We caused them a lot of problems. Both sides went for it – from a neutral's point of view, I'm sure it was an excellent game.
"We showed good spirit, we showed a lot of quality on the ball and scored very good goals – and if we can do that against a side that has been as successful as Southampton, we can take that bit of confidence that you need from that win and add that into our league form.
"You don't get given confidence, you have to earn it. We've got to keep working as hard as we did tonight and the confidence will follow.
"The FA Cup can – hopefully, tonight – breed some confidence in the players and then the next round can bring in some much-needed revenue to what is one of the smaller clubs in the division."