Gary Rowett has explained his tactical switch at half time which put Fulham to the sword in the 4-2 defeat at Pride Park last night.
With the score at 2-1 after 45 minutes and the tie hanging in the balance, Rowett hauled off Matej Vydra to introduce another midfielder in the form of Jacob Butterfield.
Fulham had been the better side in the first half and would've been left scratching their heads at the break about how they were behind, but the switch to a 4-3-3 from Rowett ensured Fulham were pressured higher up the pitch, something that led to the third and fourth goals.
Tim Ream lost the ball to hat-trick hero Dave Nugent when he put pressure on the centre back, while David Button's loose throw was picked up by Johnny Russell after Derby had boxed the Fulham defence in around the edge of the area.
Revealing the decisions behind his switch, Rowett said: "We just felt we needed to change it.
"I have said before that we like to be pro-active. I didn't want to go out second half and just hang onto the game, I didn't think there was any point doing that in our position.
"We wanted an extra midfielder. It was tough on Vyds (Matej Vydra) but he is a team player, he understands and luckily for me we ended up winning the game rather than losing because that makes my decision a lot easier.
"It gave us a bit more control and we certainly got out to the ball better and pressed much better, and caused them far more problems.
"When the ball was turned over in transition we had the quality, the pace and the incisiveness to hurt Fulham."