A superb strike from Conor McAleny made the finale nervier than it might have been.
But Kenny Jackett heralded a 2-1 victory at Highbury Stadium that reignited Pompey’s stuttering play-off push.
A goal in each half from Jamal Lowe and Oli Hawkins saw them move to within two points of the top six.
And despite a frantic Fleetwood fightback in the closing stages, Jackett felt his side were worthy of securing a maximum haul.
The Blues boss said: “We had our usual late heart-attack, although it was a magnificent strike from McAleny and it gave them hope.
“But I felt that we deserved the win overall. We had a lot of control, even if I felt we would need that second goal.
"There was a good spirit among the players and I was delighted with the win."
“Adam May had a long-range shot that hit the post and there was one cleared from the line at the start of the second half.
“You wondered if one of those might have cost us, but ultimately they didn’t. There was a good spirit among the players and I was delighted with the win.
“We grew into the game and got an excellent goal. You have to get your wide men going against a back three and we did that.
“Jamal was very effective – he shows plenty of desire to wear that Pompey shirt and perform well for us.”
Pompey fielded a starting line-up with an average age of under 23, while 21-year-old Matt Clarke was stand-in skipper.
Jackett said: “With Henderson, O’Keefe, Rose, Pitman, Evans and Thompson, it’s six very experienced players we were missing.
“But we still had a very balanced team. Adam came in and played very well – I was delighted with him and his partnership with Ben Close.
“It was a young side, but they showed plenty of promise at a time where we really needed to get going.
“Matt deserved the armband on his performances. He’s committed his future to us with a new contract and earned it.”
Kal Naismith is the latest player to book a spot in the treatment room, although Jackett is keeping his fingers crossed that the forward will soon return to action.
He said: “Kal’s got a groin injury and unfortunately didn’t make the trip. I certainly hope he’ll only be out for a few days.”