Danny Cowley has credited his squad for the levels of consistency they have maintained over the past few weeks.
Pompey have had to contend with injuries and suspensions to limit the number of players that can be used.
And yet the club are currently on a remarkable seven-match unbeaten run that includes six victories and 21 goals scored.
A trip to Ipswich is next on the cards and Cowley will continue to take a considered approach to selecting his side.
The Blues boss said: “We’re growing and improving by the day – on and off the pitch – and I think that 19 points from the past 21 available highlights that.
“We’ve really enjoyed the challenges that recent times have brought, with just 13 fit senior outfield players for a while now.
“They deserve plenty of credit because they’ve been relentless in their efforts to find a level of consistency.
“It's testament to our togetherness and spirit, as well as the individual determination and resilience of each of them.
“Now it’s the job of the coaching team to make the right decisions on selection and we sometimes have more information than the supporters.
“We can’t always divulge everything because we don’t want to let our opponents know, but we’re trying to pick the right players for the right games.
"They deserve plenty of credit because they’ve been relentless in their efforts to find a level of consistency."
“There were players who did extremely well against Accrington last Saturday and expended so much energy, so we left them out at Crewe.
“And although we only have those 13 guys available, they’re 13 very good players. It doesn’t matter how many you have in your squad, you can only pick 11 of them to start.”
Ipswich currently sit one place above Pompey in ninth spot and are currently on their own long unbeaten run.
Cowley said: “It’s a very tough game against a side who have, like us, got better as the season has progressed.
“They’ve got the best squad in the division and are well coached, so it’s certainly going to be a tough test.
“You just look at their bench on Tuesday night, which included Conor Chaplin, Macauley Bonne, James Norwood and Joe Pigott.
“Those forwards are the envy of most other sides in this division and would probably get in certain Championship teams.
“They’ve recruited well and have kept seven clean sheets from their past eight matches, while also carrying a goal threat.
“It's set up for a very good game and we’re looking forward to it after feeling the pain of what happened at Fratton Park in October. We’ll use that to fuel us on Saturday.”
Cowley is pleased that Michael Jacobs could soon be making his return to the side following a knee injury.
He said: “We’re looking forward to him coming back out on the grass and joining in with training again. That’s huge for the group.”