Pompey have a daunting run of fixtures to negotiate before the end of January.
Their next three games are all against sides firmly in the race for one of three promotion spots to the Championship.
After hosting fourth-placed Scunthorpe this weekend, Pompey travel to a Rotherham outfit sitting just outside the play-off places before Shrewsbury, currently second, visit the south coast.
And Kenny Jackett knows it is a schedule that could prove pivotal in their own hopes of finishing in the top six.
The Blues boss said: “This starts a run of games against sides who are either above us or around us in the table.
“So it’s going to be a big test of our aspirations to stay in the top six because all those teams will have the same ambitions.
"It’s about finding those right enthusiasm and quality levels to make sure we challenge the opposition and bring our fans into play."
“Scunthorpe are a very good side and were very unlucky not to go up last season – they’re also making a decent fist of it this year.
“They’ve got plenty of depth to their squad and are still looking to improve, so will be one of many sides looking for a strong end to the campaign.
“But we have a good home record and there will be a big, positive crowd in. We want to produce the right performance to lift them.
“It’s about finding those right enthusiasm and quality levels to make sure we challenge the opposition and bring our fans into play.
“Consistency, as we know, is key. The points totals are high for promotion in this division, so we need to find a way of winning on a regular basis.”
Pompey are sweating on the fitness of Nathan Thompson and Ben Close after the duo both limped off during Tuesday night’s Checkatrade Trophy defeat.
Jackett said: “Neither of them trained on Thursday and we’ll wait until Saturday if we have to because they’re important players for us. I would rate them both 50/50.
“Stuart O’Keefe has a problem in the groin area and it appears to be hernia-like symptoms, so I would think he would be out for 4-6 weeks.
“But Gareth Evans is back out running again and there could be a chance of him making the Rotherham game next week.”