Thomas Frank admitted counterpart Wayne Rooney’s triple half-time substitution inspired the second-half recovery by Derby, who came back from two down to draw 2-2 at Pride Park.
Brentford were cruising at the break after Ivan Toney scored with a penalty and Sergi Canos doubled the lead.
Bees boss Frank said: “We had an excellent first half, maybe one of our best halves of the season. We were totally in control and could have scored more than two.
“We told them at half-time that we knew Derby would come out flying, and when we saw they were making three changes, that something would happen.
“Then they got that goal after one minute – which is a very rare thing to happen – and it looks like a masterstroke by Wayne.”
Frank added: “The second half went quiet after 20 minutes and then we were on top – and then you either get that top action [the goal] or you don’t get it and we win 2-1.
“We know that next time we play this game we win 2-1, but today we didn’t and we need to move on.
“They deserve some respect for what they did to change things. They changed their shape and played longer and more diagonal balls to Colin Kazim-Richards.
“But after getting out of the first storm early in the second half, we need to do better and we simply didn’t keep the ball well enough.”
Frank was pleased to have captain Pontus Jansson back for the first time since the win over Bournemouth at the end of December.
“It’s very positive to have him back and he looked good in general,” said the Dane.
Frank paired Jansson with his other experienced centre-halfm Winston Reid, with Ethan Pinnock dropping to the bench.
He explained: “It is a very long season and of all the Championship teams we had the longest season and shortest break last time, although that is not a complaint.
“Ethan played every single minute last season more or less and has played most minutes this season, plus Winston has done well. So it was a combination of that and minor rest to Ethan.
“It is even better to have three reasonable centre-backs with Mads Bech Sorensen at left-back.”