Derby County boss Phillip Cocu felt having to chase the game from so early on proved key to his side's defeat to Bristol City on Tuesday night.
The Rams were 2-0 down at half-time and struggled to seriously trouble their opponents until after Jack Marriott had reduced the arrears in the closing stages.
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And Cocu felt the Rams didn't do enough before City's first goal to gain the momentum.
He said: "I saw a reaction after we conceded the first goal but I want to see that from the start, not once we are chasing the game.
"We are then always pursuing the opponent and the second goal is then a big blow.
"I don't know why we struggled. The pitch was good, the players are good and we were pressing well.
"But we couldn't convert the chances we created."
Cocu changed the team's shape to a 3-5-2 formation at half-time but again the Rams struggled to create much in the way of chances until late in the game.
"I felt in the second-half we were much better in the way we played and in terms of our attitude, but in the end the mistakes have proved the difference.
"Our end pass was not good enough, especially from out wide. Mistakes will happen but I don't want that to be down to a lack of focus or concentration."
Cocu added that striker Marriott may well have played more of a part in the game had he not picked up a minor knock in training this week.
He said: "Jack did well in the cup game at Scunthorpe and might have been ready to play longer but had a minor injury in training and I didn't want to risk playing him for too long and potentially losing him for longer.
"He seems to have come out of the game OK so maybe he can play more of a part at the weekend."