Victory over Charlton will give Pompey the belief they can be promotion contenders.
But Kenny Jackett warned they can’t let standards slip for a second if that’s to become a reality.
The Blues delivered arguably their best result of the season to defeat the play-off chasing Addicks 1-0 on Saturday,
It’s the first time Jackett’s men have beaten any of the sides currently above them in the League One table.
After making it six wins in their past seven games, the Pompey boss knows confidence will be high about what can be achieved this term.
His team moved up to seventh in the table, three points behind Charlton – who have a game in hand.
Jackett feels performances have to be maintained if his side are to break into the top six.
He said: ‘I think (the result) can give your players confidence they can do it.
‘If we think or I think this result is the answer, though, we’ll find out it’s not, too.
‘We need consistency and we need to be in and around the top sides.
‘We need quality but consistent quality. We must have that.
‘Defending is a quality, going forward and getting shots in is a quality and keeping the ball is a quality.
‘We need consistency in those areas to be one of the better sides.
‘I know this division very well and the better sides in the division end up with a high points total.
‘It’s maybe slightly higher in the Championship.
‘A lower points total can get you around fifth or sixth but for the top sides, it’s proving again they do look the top teams.
‘I include Charlton in that. They are a very good club with an outstanding squad.’
Jackett was delighted with the application of his players as they offered a goal threat in spells and stood firm as the home time pushed for a leveller.
The 55-year-old believes even a small drop in performance level can’t be contemplated, though.
Jackett said: ‘We’ve set some standards in terms of work-rate and desire.
‘We did well on that front, but we’re going to need to.
‘When you see Charlton and the strength of their squad in the last month, we have to work very hard.
‘With the players they have coming back from injury we have to work very, very hard to compete with them.
‘It’s very tough competing with the top sides in the division.
‘We’re capable of that but even a five-per-cent drop below that means we won’t get points.
‘Our attitude, body language and desire has to be there in every game.
‘For every minute of every single game you can’t switch off.
‘For us, we’re learning, we’re working and we’re improving.
‘We can’t drop our standards by even five per cent.
‘We can’t if we want to compete with a squad as strong as Charlton’s and teams at the top of the division.
‘There are a lot strong teams at the top and it’s where we are all aspiring to be.
‘It’s not something which is just a given though. You have to earn it. You have to earn every single point.
‘Any win is hard-earned and it certainly was against Charlton.’