Andy Awford felt Pompey deserved all three points after seeing his side hauled back for a 2-2 draw with the last kick of the game at Carlisle.
The Blues fell behind early in the contest before a stunner from Jed Wallace and Matt Tubbs put the visitors in command.
Awford’s side then bossed the game after the break, without carving out many clear chances at goal.
But even though four minutes were indicated for stoppage-time, Pompey were made to pay in the fifth minute as the home side netted their late leveller.
Awford said: ‘We’ve gone behind early but we put in a good performance after that and we should have won the game.
‘Jed scored a magnificent goal and we needed something special to get us going.
We’ve gone behind early but we put in a good performance after that and we should have won the gamePompey boss Andy Awford
‘But we dominated the game after the first 15-20 minutes.
‘I’m a bit disappointed we didn’t score more goals, in all honesty.
‘I don’t want to criticise referees because they have a very difficult job.
‘But the easiest thing is to get the time right and we were way into the fifth minute of stoppage-time.
‘We still need to do better in defending that and seeing it out but the game should have been over by that point.’