Michael Appleton cursed Pompey’s profligacy after errant finishing cost his side two precious points.
The Blues produced a second-half onslaught as they overran Bristol City during the second half of Saturday’s vital relegation clash.
Appleton’s troops fired in 15 shots compared to a mere two from the visitors.
Yet just three of those 15 were on target as the Fratton Park encounter finished goalless.
It was more frustration for Pompey whose continued struggle in front of goal is edging them closer towards relegation to League One.
They have now managed to score just two goals in the last nine matches – one of which was a Greg Halford penalty.
And Appleton admitted the situation was infuriating.
He said: ‘I thought they were incredible in the second half – we created 15 chances in the match overall.
‘We need a goal, we know that, and it’s easy for me to say to the players “just relax when you get into that situation and let it be natural to you”.
‘We train all week, we do lots of crossing and finishing, we try to recreate situations that happen in the game.
‘But probably the biggest disappointment was we never made David James work hard enough.
‘There were a few times when he had to make saves but didn’t really have to overstretch.
‘That maybe was down to a lack of contact with the ball or just snatching at it.
‘But you cannot get too disappointed with that second half, it was hard for me to be too over critical.
‘It’s a situation we are in at the minute where we get into fantastic positions, have fantastic chances but are just snatching at them a little bit.
‘There is a lack of confidence in front of goal with some of the players, maybe a little bit psychological with one or two of them, but I can’t ask for much more from them.
‘Performance-wise they were outstanding.
‘And if they get into those positions again we need to be a bit more clinical.
‘I have asked them who is going to be the one to be the hero, so to speak?
‘Who is going to be the one to take it by the scruff of the neck and take that opportunity?
‘Everybody talks about the first goal and it is absolutely key because it spells out what is going to happen for the rest of the game.
‘Hopefully that will happen tomorrow against Birmingham.’
Dave Kitson was dropped from the Pompey squad against the Robins, while Kanu was again missing with his long-standing back problem.
In their absence, the main culprits in spurning the chances were joint-top scorers David Norris and Luke Varney.
Both have returned to the side in the past few weeks following lengthy injury absences.
And Appleton believes that rustiness may have had an impact on their effectiveness in front of goal.
He added: ‘Probably having been out has affected them.
‘When you have not played for a while, you are a bit rusty and trying to get full fitness.
‘When they go on some of their runs – and they make fantastic runs – it probably takes them a little bit longer to recover than they normally would.
‘Then when you get into those final goal-scoring opportunities your legs become a little bit heavier because you haven’t got the full match fitness.
‘In the next 10 games they will get fitter, stronger and better, so hopefully that will result in a couple of wins.’