With six games of the season remaining, Pompey are still very much in the hunt for automatic promotion.
But Kenny Jackett knows his side cannot afford to drop many points if they are to overhaul Barnsley and Sunderland to finish in the top two.
They are three points behind the latter – who currently occupy second spot – ahead of Saturday’s clash with Rochdale.
And Jackett is not going to worry too much about how their rivals at the top of the League One table are faring.
The Blues boss said: “We’re on 77 points and we’re going to need 90-plus. We know that there’s not much margin for error, but we’re capable of reaching our aim.
“It is realistic for us to get into the top two and although we don’t need perfection, we need something near it.
"At this stage of the season you keep one eye on what else is happening around the country, but the important thing is we maintain our form."
“We have to really go for it now – and have a fantastic crowd behind us that we know will back us all the way.
“At this stage of the season you keep one eye on what else is happening around the country, but the important thing is we maintain our form.
“We’ve suddenly put some wins together to give us some momentum and so we have to keep our foot to the floor.”
Pompey face a Rochdale outfit who have recently climbed out of the drop zone since Brian Barry-Murphy took charge.
Jackett said: “The new manager has done very well and achieved both good results and performances.
“We never look at any game as being easy and know that every point we collect is hard-earned – we showed that last week.
“Rochdale are fighting for their lives down at the bottle and will do everything they can to maintain their League One status.
“But we should have confidence and I’m sure our attitude, endeavour and quality will encourage our passionate fans.”
Jackett has no new injury concerns for the Fratton fixture, but it is also too soon to welcome back any fresh faces.
He said: “We’ll be selecting from the same group. Andy Cannon played for the reserves in the week, but has been out for a while and won’t be considered.
“There’s another game scheduled at Bournemouth next Tuesday, which will help. Dion Donohue and Viv Solomon-Otabor will hopefully be available for that.”