Guy Whittingham admitted Pompey’s display in the opening 15 minutes cost them dearly at Pride Park today.
The Blues suffered a 3-1 defeat against Derby, leaving them without an away victory since March.
However, joint caretaker boss Whittingham believes it could have been a different story for his side had they performed better in the opening stages of today’s clash.
Craig Bryson opened the scoring for the hosts after two minutes, before Chris Maguire extended their lead on 14 minutes.
Jamie Ward made it 3-0 just after the half-hour mark, before Jason Pearce scored a consolation for the Blues on 79 minutes.
‘You’re annoyed and frustrated because you hope you’ve prepared the team in the right way,’ admitted Whittingham.
‘And we’ve got to take it on collectively that maybe we didn’t.
‘Maybe we didn’t stress the fact that we had to make sure that the first 15 to 20 minutes – wherever you are away from home – that you keep the crowd quiet, you don’t build up the confidence of the home team and you don’t concede a goal.
‘But they (the players) are a good bunch of players and they’re honest players and there was no-one more disappointed than them at half-time.
‘They’re passionate about their football, they’re winners and they want to win, but sometimes you need to take the lead and tell them what needs to be done straight away.
‘As a collective we didn’t do that in that first 15 minutes.’