Aston Villa boss Dean Smith revealed his side practised penalties for four weeks ahead of their shoot-out victory over West Brom at The Hawthorns.
A first-half header from Craig Dawson levelled the tie on aggregate, with the Villans unable to break down 10-man Albion over the 90 minutes and the 30 minutes of extra-time that ensued.
Both Mason Holgate and Ahmed Hegazi saw their penalties saved by goalkeeper Jed Steer as the visitors gained the early advantage, but despite Albert Adomah blasting his wild spot-kick over the bar, top scorer Tammy Abraham tucked past Sam Johnstone to secure a 4-3 win for Smith's men.
And Smith - who recently guided Villa to a club-record 10-game winning streak - attributed his side's success from 12 yards to a month's practice on the training ground.
After his side booked a spot in the play-off final for the second year in succession, he told Sky Sports: "To be honest, we've worked very hard; from the day we knew we were in the play-offs, we started working on penalties.
"We've been doing this for four weeks: we had a plan of who would take them, and the goalkeeping coach works very hard with Jed Steer in terms of which way the opposition would go.
"There were about three or four of them who wanted the fifth penalty! Tammy Abraham is a prolific finisher and he's shown that tonight.
"Everybody knows the rewards by going and doing it [getting promoted] and it's going to be tough because they are two good teams, Leeds and Derby. Albion put up a really good defensive performance over the two games, made it difficult and that's why it ended up going to penalties."
However, despite advancing to the Wembley showpiece, the 48-year-old expressed disappointment that his side had suffered defeat inside the 120 minutes of open play.
The boyhood Villa fan added: "I'm not that emotional, to be honest! I'm very proud of the lads, but the disappointing thing is that I can't believe we lost the game tonight. I felt we should have won the game in normal time but our quality wasn't good enough in the final third.
"We've had a lot of the ball all game again, but that's job done, I suppose, in terms of getting to the next game at Wembley."
West Brom caretaker Jimmy Shan later explained how he couldn't sum up the feeling of disappointment as the Baggies' hopes of an immediate return to the Premier League were ended on home turf.
"The boys have put everything into that tonight, the fans too," he said. "I called on the boys to have application, a forward-thinking mentality, have a threat, for the fans to get behind us and both parties have done that. I thought we were good tonight.
"It's difficult [going down to 10]. You lack an out-ball, a get-out ball and it's difficult to break from that deep block, but I think the boys self-managed, self-organised and I think Villa found it difficult to break us down at times. Credit to the boys, how resolute in their character they were to stay within the game and take it through to penalties.
"I think if you look how we finished the game, we lacked penalty takers on the pitch: Stefan [Johansen] would've taken one, Brunty [Chris Brunt] would've taken one, Matty [Phillips] would have taken one, Jay [Rodriguez] would have taken one.
"As the game's going on I'm thinking, just hang in there, but in reality I'm seeing that we haven't got natural penalty takers on the pitch."