Nicky Shorey dismissed talk Pompey’s hopes of making the play-offs are over.
And the Blues defender believes repeats of the gutsy display at Newport County can still see his side finish in the top seven this season.
Andy Awford’s side could count themselves unlucky to return empty-handed from Rodney Parade after Saturday’s 1-0 defeat.
The display of referee Michael Bull was central to the result as he failed to give two penalties to Pompey and allowed a disputed winner from Mark Byrne.
The result now leaves Pompey 11 points from the play-off spots and just five points above the bottom two.
But Shorey is insistent more performances like that at the high-flying Welsh side will pay dividends.
The left-back said: ‘A lost cause? No chance. We’re not writing anything off.
‘We believe we can put a run together and you can see why in that performance.
‘We want to do something this season.
‘We won’t be waiting until next season, so that is what we will be fighting to do now.
‘This club is definitely ambitious and we know what it means to the fans.
‘So we will be going hell for leather to make it happen.
‘If we perform like we did we will win more games than we lose.
‘So we have to keep believing. If we keep putting in performances at that level we will be okay.’
It was the position of Aaron O’Connor in keeper Jones’ line of vision for Byrne’s goal which angered Pompey.
Shorey said: ‘We just feel disappointed it’s cost us the game.
‘We think we did enough to get something from the game.
‘They’ve nicked the goal and we aren’t happy about the way it’s been given.
‘We have to take it on the chin but, trust me, that’s not always an easy thing to do.
‘We’re not happy about it but there’s not a lot you can do.
‘Whether the player has got a touch is irrelevant to us.
‘But we have to get on with it – and we got on with it pretty well after the goal went in.’
Referee Bull ignored his lineman’s flag for the only goal of the game.
But it was not giving two spot-kicks which further angered Pompey.
A handball on Shorey’s late shot was one of the claims, with a blatant trip on the impressive Wallace by Byrne the other. Shorey said: ‘Jed has done well.
‘The player has said it’s a penalty and I think anywhere else on the pitch it’s a free-kick.
‘It hasn’t quite gone for us, though.’
The goal changed a game Pompey had impressed in for long periods against an outfit unbeaten at home in the league this season.
Awford’s men then threw everything at Newport in search of a leveller but their efforts came up just short.
Shorey said: ‘The lads did well at the end. They are sitting in trying to protect their lead and that made it easier for us.
‘Some of the play was very good.
‘It’s a tough fixture but we have acquitted ourselves very well.’