Paul Cook criticised the ‘minutes of madness’ which have left Pompey’s promotion aspirations in tatters.
Saturday’s 2-1 Fratton Park defeat against rivals Plymouth left them six points off the automatic promotion spots with one game in hand.
Yet Cook’s side had been leading 1-0 entering the 84th minute.
Goals from Jamille Matt and Gregg Wylde inside a two-minute spell earned Derek Adam’s team the points in a heart-breaking finale for the Fratton faithful.
Pompey failed to make their dominance pay when they missed chances, but Cook also rounded on their late defending.
He said: ‘I am disappointed with the result.
‘When you are building teams and trying to put them together you must be built off a solid base.
‘Yet we haven’t seen the game out, we haven’t had enough 1-0 wins.
‘It happened so quickly, we became such a disjointed team in a blink.
‘Then in our attempts to get back in the game we were never going to by playing like that, we didn’t string two passes together.
‘So all of a sudden in the space of a few minutes we have gone from a strong team to that – and that is what goals do for you. Goals give lads confidence and energy, and in the opposite way it takes the life out of you.
‘Matt Clarke and Christian Burgess were excellent for such long periods and probably Clarkie has a little five minutes of madness and all of a sudden we are beaten 2-1.
‘Paul Jones was excellent but we think might have done better with the cross, so all of a sudden there is a couple of minutes of madness in there and we have got to make sure we try to manage that.’
Cook had substituted Adam McGurk and Gary Roberts for Gareth Evans and Marc McNulty before the late turnaround.
Roberts had been suffering the effects of a bang to the head following a Peter Hartley elbow.
By the time Conor Chaplin was introduced in the 88th minute for Ben Davies, the Blues were heading to a disappointing defeat.
And Cook admitted he had regrets over the substitutions.
He added: ‘You have to look at substitutions, players, personnel.
‘When you put a negative sub on people call you a negative manager and at that stage of the game I feel a negative substitution was something I should have done.
‘Instead I went positive with McNulty. I do regret that at the minute, but that is only with hindsight and hindsight is a wonderful thing.’
– NEIL ALLEN