They have developed into frustratingly regular set-backs since the turn of the year.
Yet during his diagnosis, Kenny Jackett is adamant fitness and character issues are not behind the flurry of late goals which have proven increasingly costly to Pompey’s ambition.
There doesn’t look a stand-out thing, not one type of goal, and we have lookedKenny Jackett
Joe Mattock’s header in the first minute of time added on handed Rotherham a dramatic victory on Saturday.
It followed similar heart-breaking outcomes at Bristol Rovers in League One and then against Chelsea under-21s in the Checkatrade Trophy.
That is now three times in four matches since the dawning of 2018 that the Blues have suffered last-minute defeats.
And while Jackett concedes there is an issue, he doesn’t believe there is an obvious pattern behind their cause.
He said: ‘At Bristol Rovers you could see the flow of the game was coming against us – and it was tough. Perhaps the goals were coming.
‘But I thought at Rotherham we weathered the storm and the stadium had gone a little bit dead, it was petering out slightly.
‘Then we hit a goal-kick that has gone off, the ball has then somehow ended up down our right-hand side when we haven’t really done enough to keep it out of there and then they had a chance on the far post when Jamal Lowe’s not stayed with his runner.
‘It is about game management. I wouldn’t necessarily put it down to fitness or character because our team shows good fitness and good character every week – they do show those things.
‘Saturday was a frustrating one because it seemed like we had weathered a very rough storm for the first 20 minutes of that second half. Bristol Rovers was slightly different in that it felt like the goals were coming.
‘Being cynical, in the Chelsea game their player ran 40 yards with the ball – you need someone who could catch him to bring him down.
‘So I don’t think there is any one outstanding thing.
‘It is down to some game management and experience of where to put the ball at the right time and how to slow things down. That can help in any situation.
‘There doesn’t look a stand-out thing, not one type of goal, and we have looked.
‘However, they all have been key goals and one way or another we have to eradicate it.’
The New York Stadium scoreline was particularly harsh on the outstanding defensive pairing of Christian Burgess and Matt Clarke, while right-back Nathan Thompson also warrants praise.
Jackett is convinced there must be improvement further up the pitch to ensure such goals can be cut out.
He added: ‘We put our bodies on the line literally, it was that type of period, and particularly Thompson, Burgess and Clarke were responsible for that.
‘But you have to look at both sides of the game, not just defensive.
‘If we can be better on the ball and if we can do more going forward then I think we’ll get more clean sheets as well.
‘In the end, pressure tells and sometimes it is coming on us too much and the volume of pressure has resulted in goals.’