Kenny Jackett believes his side are capable of turning around their poor form.
Pompey have won just one of their eight league games since the turn of the year and were beaten 3-1 at Southend on Saturday.
They soon have another chance to get the campaign back on track with a midweek trek to struggling Fleetwood.
It is a quick turnover, but Jackett is confident his side can produce an improved performance at Highbury Stadium.
The Blues boss said: “It’s enough time for us to get the message across. It’s not a new one – it’s something you repeat on a regular basis.
“We’d started the game okay on Saturday and had a decent chance through Conor Chaplin that left us encouraged.
"You look at the table and we’re still within touching distance, which is a good thing. We can’t keep saying that, though, and not doing anything."
“But the passiveness of our defending was disappointing and there was a spell when we were at sixes and sevens whenever the ball came into our box.
“That needs to change and it will change because our players are definitely capable of much better than that.
“You look at the table and we’re still within touching distance, which is a good thing. We can’t keep saying that, though, and not doing anything.
“Our target has been staying on the coat-tails of the top six and being good enough to get in there. That is still the same mentality for us.”
Pompey face a Fleetwood side who dismissed manager Uwe Rosler following Saturday’s 3-0 defeat at Doncaster.
Jackett said: “It can change things sometimes and have an effect, but you have to get your own team sorted and overcome whatever obstacles come along.
“You’re always aware of the opposition and their strengths and weakness. You won’t win the game if you don’t improve on your performance, though.”
Pompey will be without Brett Pitman and Gareth Evans after the duo limped off against Southend at the weekend.
Nathan Thompson is also absent as he begins a four-match ban, but Matty Kennedy has returned from an ankle problem.
Jackett said: “Evans and Pitman will be out for weeks rather than days, while Nathan is suspended, so we’ve got three guys who are definitely out.
“But we knew it was going to be difficult for the first two to make it when they left the pitch on Saturday.
“Matty’s okay – he trained partly on Sunday and fully on Monday. We’re expecting him to be fine on Tuesday.
“We’ve got a well-balanced group going up to Fleetwood and everyone will be able feature in their natural position.
“There are opportunities for young players and all of the squad were enthusiastic in training, so I think we’ll get a really positive response.
“We’ll see plenty of energy and they’ll be prepared well by me and the coaches, so they will certainly be ready.”