Paul Cook believes inconsistency has ripped up Pompey’s away-day winning formula.
The Blues registered the fifth-best League Two record on their travels last season, with three of the four promoted sides among the notable scalps.
I have spent so much time watching the games that I have started to get brain achePaul Cook
This time around, however, they have one win and three defeats from their opening five league fixtures away from Fratton Park.
That run has become an early season concern – especially with the next two matches on the road.
On Saturday, Cook’s troops visit Leyton Orient, followed by a trip to leaders Plymouth.
And he believes he has identified the costly issue.
He said: ‘If you look at us last year when we were winning at Plymouth, Northampton and everywhere, we have obviously changed something because we were winning.
‘So all of a sudden what is it that we have actually changed?
‘It’s the inconsistency in our play – and what we must do is go back to the basics of whatever formation we play and work dead hard.
‘Let’s give our supporters something to shout about with honesty and effort – and everything else will take care of itself.
‘If anyone is watching clips from our game against Reading under-23s the other night, the honesty in our lads’ performance is there to see.
‘You are searching to get all your balances right and when you get one right, another problem arises. That is why you must be consistent in what you do.
‘I have spent so much time watching the games that I’ve started to get brain ache!
‘I want to watch DVDs of us being consistent all the time.’
Defensively, the Blues have crumbled in the past two matches, with individual errors the downfall.
Cook’s men had impressively started the season with four clean sheets in their opening six league fixtures.
However, they have now conceded nine in the subsequent five matches to establish the issue as a chief concern.
It’s a back four which welcomed back Matt Clarke for last weekend’s visit of Doncaster – and he will tomorrow again keep his place.
And in terms of defending, Cook is demanding improvements from his spluttering side.
He added: ‘We train every day with similar stuff, everything is about running forward, the ball goes forward your position must go forward.
‘The big one is our back four, who unfortunately have the ability to make the pitch bigger.
‘If we are marking Adebayo Akinfenwa, for example, we won’t squeeze the game and instead just mark him.
‘He likes to be on the 18-yard box so “We’ll keep you there, no problem” – but they need to squeeze up.‘Don’t allow people to dictate your starting position, we should dictate everything on the pitch.’