Danny Hollands spoke of his Pompey pain after Shrewsbury’s fluke winner left Andy Awford’s side reeling.
Central defender Connor Goldson grabbed a 72nd-minute winner when his deep cross sailed over the head of Paul Jones and into the Blues’ net.
It was heartbreak for the visitors, who had been worthy of a point at Greenhous Meadow – where the Shrews are presently unbeaten this season.
Jed Wallace’s third-minute penalty had earlier been cancelled out by James Wesolowski’s strike from the edge of the area.
However, Pompey appeared to be heading for a hard-earned 1-1 draw until Goldson’s fortuitous cross broke their hearts.
Hollands said: ‘It is disheartening to lose it in that way.
‘It is a tough place to go, we have worked hard, they have had a few more shots than us but nothing massive.
‘We ground out what we thought was a good point.
‘So to lose to a freak goal kicks you right in the stomach.
‘It was a fluke. Anyone can see that.
‘Any footballer knows that he was getting the ball out from under his feet and looking to cross it and it has gone into the top corner.
‘That sums up our luck at the moment.
‘The first goal we felt there was something we could do as a team to prevent.
‘But the second one you have to hold your hands up – it is just one of those things.
‘When luck is on your side it happens.
‘Hopefully – throughout the season – we will get our bit of luck and things will turn in our favour and we do something like that.
‘Even their manager has come out and said he tried to cross it.
‘You can’t stop it from source.
‘It is not like he is even crossing it from the byeline.
‘You don’t mind him crossing it there, you are going to deal with it.
‘Then it has gone over the keeper and into the top corner.
‘At the end of the day you expect them to have a bit more possession – they are the home team.
‘But I felt they didn’t really go anywhere with it – then they got a fluke winner.’
Wallace’s goal represented the Blues’ first for 463 minutes on the road in the league.
Nonetheless, the defeat saw them sink to 13th spot as they failed to build on triumph over Stevenage in the week.
And for Hollands, the manner of the Shrewsbury loss summed up how their season is faring.
He added: ‘It is not really going for us at the moment, which is frustrating.
‘But you have to keep focused and hopefully we’ll get our just rewards.
‘We have belief in ourselves and the manager and what we are doing.
‘Hopefully we can get our bit of luck soon.
‘We started off the season well, had a little bit of a dip and the last couple of games have been better performance-wise.
‘Now we’re looking to get three points against Carlisle on Saturday.’