Pompey slipped down to sixth spot in the League One table following defeat at Peterborough on Saturday.
But if they can beat Fleetwood on home soil on Tuesday evening, then Kenny Jackett’s side would be level on points with Rotherham in second.
It shows just how tightly packed things are at the top of the standings, with five teams currently on 59 points.
Pompey are one of them and with three successive games at Fratton Park, Jackett knows they can make a statement on their promotion credentials.
The Blues boss said: “We’re playing Fleetwood and Sunderland are at Bristol Rovers, so there’s an opportunity for some of the sides to affect the table.
“It’s a game in hand for us and we have to seize that opportunity if we can – it’s a big chance and we want to be at our best.
"This league is so tight at the top and we have to be aware of the fact that a win on Tuesday could really help us."
“We also have to recognise that we can – and need to – play better than we showed at Peterborough on Saturday.
“When you’re a side that has a lot of games, like we do, you need to be able to move on pretty quickly.
“Immediately you’re looking at the next fixture and how your team is going to adapt, if that needs to happen.
“This league is so tight at the top and we have to be aware of the fact that a win on Tuesday could really help us.
“Right down to ninth or 10th place, it’s incredibly open. It’s difficult to know what points total will be needed, but it will be high.”
Pompey are only above Fleetwood on goal difference, with the visitors heading south unbeaten in 11 matches.
Jackett said: “They’ve had a great run and, particularly since the turn of the year, their defensive record has been fantastic.
“There are genuine aspirations for them to finish in the top six and then, ultimately, get into the Championship.
“Joey Barton has done a very good job there and he’s managed to build a really strong unit. They’ve got some good players.”