Paul Cook rued the Pompey ‘blip’ which is threatening to rip up plans for an automatic promotion spot.
The Blues have dropped out of the play-offs following a third defeat in six League Two matches.
They have now won only one of their last seven in the league.
The latest blow to their aspirations of making the top three was delivered at Barnet last night.
Martin Allen’s side clinched a 1-0 victory through ex-Pompey striker John Akinde’s 41st-minute penalty.
It was no more than the Bees’ first-half display deserved as they physically dominated the visitors with embarrassing ease.
My job now is to manage. The reason I was brought to the club was to manage, the reason other managers have been sacked is it’s a difficult jobPaul Cook
It was a far improved performance after the break from Cook’s men, yet they could find no leveller.
With 15 matches remaining, the current dry run is challenging even the safety net of the play-offs.
And the manager recognises their problems must swiftly be reversed.
He said: ‘We have hit a bit of a blip, it’s a really poor time for us in the season.
‘My job now is to manage. The reason I was brought to the club was to manage, the reason other managers have been sacked is it’s a difficult job.
‘Last night we tried our best to play the game the way I like the game to be played and unfortunately never created enough clear-cut chances.
‘You know you are going to be put under pressure coming to Barnet.
‘It is something we had spoken about and we felt if we saw the game out with the physicality we might open them up eventually.
‘They showed great intent to put us under pressure.
‘You could see yourselves with long throws and physicality and fighting and scrapping, we had to be brave on the ball and play more football.
‘It took us until half-time to make the players believe in themselves to do that. We totally dominated the second half without really looking like scoring.
‘You expect Kal to put that chance away with his left foot, maybe that would have given everyone a lift but unfortunately it hasn’t.
‘We don’t want to come off at the end and be given abuse by our own fans – that is not what the game is about. We want to send our fans home happy.
‘Unfortunately we didn’t last night and I can understand their disappointment.
‘I have no issues with it but sometimes criticism must be constructive.
‘The reality is I have to lift the players for Saturday and the players have to lift the supporters.’
Pompey’s woes deepened with Gary Roberts forced off after seven minutes with a hamstring injury.
The problem had troubled the midfielder after last weekend’s draw at Yeovil, ensuring he didn’t train in the build-up to last night.
Meanwhile, Cook declined to comment on the role of referee Philip Gibbs in awarding the decisive spot-kick following Adam Webster’s challenge on Akinde.
It was a decision which, in particular, left the away fans behind the goal fuming.
He added: ‘You could be there all night criticising referees, the reality is they go for you and against you.
‘You have 90 minutes to win a football game. You should never have to rely on one split-second decision.’