Richie Barker has spoken of his delight at Jed Wallace’s diamond-encrusted display.
And the Blues boss has admitted he would consider employing the system again.
It may have been a 1-0 home defeat to York at the weekend, but Barker was pleased with how the introduction of the new formation fared.
Tonight Pompey travel to league leaders Rochdale, with matches to remain in League Two ticking down.
The manager is keeping his system under wraps, but would have no qualms fielding a diamond again if required.
He said: ‘We fielded a diamond because we felt we could play through them.
‘We thought they were going to try to press and there would be opportunities to get the ball in the hole, which I thought Jed did really well.
‘We also felt they were arguably less of a threat full-back-wise so it was worth trying to isolate the centre-halves, which I felt worked to a certain extent.
‘I was a bit surprised Jed didn’t get man of the match, to be honest. I thought he was excellent and he looked backed to his best.
‘Maybe that suits him a little bit more in terms of playing with a freedom with the natural enthusiasm he has got.
‘Possibly, I would use it again if it suited the team we were playing against and it was going to isolate their weaknesses.’
Wallace, Ben Chorley, Rhys McCabe and Ryan Taylor were the four changes for the Fratton Park fixture with York.
And Barker defended the continued absence of a settled Pompey side.
He added: ‘You can’t keep accepting that if you don’t win the game you are going to throw the same people out.
‘You have to try to find what the winning formula is going to be.
‘In terms of personnel, we have a lot of players who can come in and out – it doesn’t really weaken the team and it doesn’t really strengthen it either.
‘We have a lot of players who are probably fairly similar.
‘Certainly in the first-half, before Ben’s sending off, we created more chances than we have probably created.
‘They were not necessarily real clear-cut ones, but in terms of entries into the 18-yard box it was more than we have done for a while. We didn’t win the game, however.
‘To have had almost half the game, more possession, more shots, and more corners – which I have to say were pretty poor – when you are down to 10 men, that is not bad going.
‘But we didn’t win the game and that is the important thing.’
Rochdale are currently two-points clear at the top.