Guy Whittingham believes his players are finally toughening up to perform effectively in League Two.
The Blues ground out a 1-0 victory over managerless Bury on Saturday to maintain their recent improved form.
It was a gutsy, uninspired display from the hosts, yet encouragingly showed a dogged defensive resilience.
The clean sheet was a second in a row at Fratton Park and only a third in the league overall this season.
That’s now three wins and a draw since the York debacle which prompted an overhaul on and off the pitch.
And Whittingham is convinced his side are now proving they have the strength to start climbing the table.
He said: ‘You have got to be tough in this league and it is something which is growing.
‘We are developing into a side that realises it is not always about how you play with the ball, it’s often how you play without the ball.
‘And I think we did that fairly well on Saturday.
‘We obviously didn’t concede so we did that well enough and that was the pleasing side of the game.
‘We defended well, there were some last-ditch tackles and, for all the pressure Bury had, Phil (Smith) didn’t really have too many saves to make.
‘Bondz again, Sonny, Joe and Yassin, they all got headers in when it was vital they did.
‘We ground it out for sure and everybody on that pitch had a part to play in that.
‘The substitutions played a big part.
‘I thought Ryan Bird did well and gave us that release to chase things up front.
‘And when Gavin Mahon and Andy Barcham came on they made us a little bit more energetic in the middle.
‘When you are not doing so well on the ball you have to work hard.
‘I don’t think we have had a game this season where so many players have not done well on the ball.
‘We’ve had games where people haven’t worked hard enough – but we haven’t had games where people haven’t done well enough on the ball – but what’s pleasing they ran their socks off.’
Bondz N’Gala grabbed the only goal of the game when he headed home a fourth-minute Ricky Holmes corner.
The centre-back has netted three times in his last two Fratton Park appearances.
Yet curiously Pompey could not match the early momentum which brought them that breakthrough.
Instead it was Bury who rallied and had the hosts hang ing on for victory.
Whittingham added: ‘Can you score too early in football?
‘I don’t think so – but maybe we just took our foot off the pedal a little bit from where we started because it was a fairly bright start.
‘Perhaps that is something which slipped into the psyche.
‘No player goes out there to play badly.
‘But you cannot go out there and play badly and not run – but we ran around on Saturday.’