Steve Cotterill has lauded the defensive backbone which has helped Pompey close in on a post-war record.
The Blues have not conceded a goal since newly-paired central-defensive duo Ricardo Rocha and Greg Halford were teamed up five matches ago.
It’s a double act which has given goalkeeper Jamie Ashdown some much-needed protection as Cotterill’s men have eased clear of the relegation zone.
Ashdown has now gone 506 minutes without picking the ball out of his net.
Another shut out against struggling Sheffield United on Saturday will see the stopper equal the club’s league record of six successive clean sheets, established in the 1978-79 campaign under the management of Jimmy Dickinson.
It has been a remarkable turnaround in the fortunes of a Pompey side whose glaring defensive inadequacies had become such a painful headache for their manager.
But finally the Blues boss has struck gold with Rocha and Halford – the seventh central-defensive partnership used during this Championship campaign.
He said: ‘When Ricardo was out of the team he spent a fair while injured, then he came back, then he got injured again.
‘I think that time he spent training and getting stronger meant he could properly get over that hamstring injury.
‘Then sitting on the bench for a couple of games probably made him think “I actually don’t like sitting here too much”.
‘There was always a time he was going to get an opportunity but it was going to be when the time was right.
‘The time has ended up being right and we have got a pairing together that have done okay so far.
‘As it stands at the moment, these two haven’t got too much competition because they are playing well.
‘We’ll have competition for places if either of these two drop their guard.
‘Then again, it’s all about getting the right partnership. It’s about partnerships back there.
‘It’s not about the individual – centre-halves always need a mate.’
Rocha has re-established himself in the Pompey side of late, producing his best football since the end of last season.
As for Halford, he has had to adjust to playing a new central-defensive role.
The versatile performer has learned from scratch having never operated in that position before.
Yet, nine games in, he continues to impress, while the clean sheets keep being racked up.
And Cotterill is delighted with the Wolves loanee’s rapid development at the heart of his defence.
He added: ‘Greg has done well there.
‘He’s a good footballer and I do like that.
‘If you can have a good footballer at centre-half who can also be decent in the air for you it’s like winning the lottery because there are not that many about.
‘The big problem with Greg is sometimes, just when he thinks he’s cracked it, something will go wrong.
‘You have to concentrate a lot more at centre-half than you do at full-back or in midfield because you are almost last chance saloon before they get to your goalkeeper.
‘His positional sense has been very good, his football has been very good.
‘I suppose we can’t ask for too much more.’