Mikkel Andersen played down his first-half heroics and conceded: I should have saved Swindon’s opener.
The Pompey keeper made a string of superb stops to keep out a seemingly-constant barrage from the Robins in the opening 45 minutes, with at least two wonder saves among them.
But just when the Blues appeared to have got out of jail to get to half-time at 0-0, Matt Ritchie’s smart shot beat Andersen at his near post – the cardinal sin for any goalkeeper.
Andersen, who is on loan from Reading, said: ‘I was happy with some of my saves but then to get beaten at your near post is never a good thing for a goalkeeper.
‘It was so frustrating and disappointing to concede right at the last moment of the first half.’
Andersen was nowhere near as busy in the second period as Pompey rallied, but now he is looking for that late improvement to continue.
He said: ‘We know we had a real go at the end and put in a decent performance.
‘It’s disappointing to lose at home again.
‘But now we need to put in the same kind of effort at the weekend at Notts County.’