League One’s joint-meanest defence stands top of the table undefeated.
Yet assistant manager Joe Gallen believes improvements must still be made by a back four that’s leaked only five goals in their opening eight league encounters.
Just Barnsley and Blackpool can compare to Pompey’s defensive record at this early stage of the campaign, with the trio representing the most miserly in the division.
For Gallen, however, Peterborough’s consolation last weekend was a sight which irked, irrespective of a key victory for the visitors.
Posh’s top-scorer Matt Godden netted in the fourth minute of time added on, albeit the Blues still holding on to win 2-1.
It deprived keeper Craig MacGillivray of a fourth clean sheet of the league season.
But, more importantly for Pompey’s assistant boss, that strike demonstrated how defensive standards must continue to rise.
Gallen said: ‘After Peterborough we were disappointed and wanted a clean sheet. Why not? I thought we defended very well.
‘I understand why fans don’t like it when the ball gets taken into the corner flag, but that is exactly where it needed to go in that game, because we had scored two and don’t need to score another really.
‘With three or four minutes to go in stoppage-time, 2-0 is a great scoreline away from home, but we had too many players flooding forward and were very open.
‘Then when the ball is turned over they went straight through us and scored.
‘We were disappointed with the last seven or so minutes and it’s something we need to look at and eradicate quickly because in another game it could have ended 2-2 – and I don’t think it deserved to be 2-2.
‘It is something we need to work on, concentrate on and learn.
‘There is a lot of pride forming in terms of us not conceding goals, not conceding chances, that has been the backbone of our season so far – and if you do that it doesn’t take too many goals to win.’
Pompey entertain Wycombe on Saturday, seeking to stretch their lead at the top of the table.
And Gallen has challenged the Blues to maintain what has been an excellent defensive record, regardless.
He added: ‘Kenny (Jackett) has a saying that zeros and ones against gets you points, but I have to say we are disappointed Peterborough scored.
‘They had another chance with Siriki Dembele and, on another day, that could have ended 2-2.
‘It’s something we have to improve upon and something we cannot let happen again.’