A run of four games without a victory had left a big dent in Pompey’s hopes of securing League One promotion.
But a home success against Bristol Rovers means it is now just goal difference keeping them out of the top six.
Ronan Curtis scored the game’s only goal – which confirmed relegation for the visitors – after linking up nicely with George Byers.
And while he feels there is room for improvement, Danny Cowley was delighted to see a return to winning ways.
The Blues boss said: “It was a really good goal, with some great play from Ronan and a nice bit of improvisation from George, then a super finish.
“We’re really pleased with the outcome and it was a very important win – I thought that we were excellent out of possession.
“It was probably the best we’ve been in terms of pressure applied, our counter-press and duels on the halfway line.
"We’re really pleased with the outcome and it was a very important win – I thought that we were excellent out of possession."
“We dealt with the direct play of Bristol Rovers very well and the defensive line was significantly better than Tuesday.
“In possession, our counter-attack was a threat throughout the game, but our ability to gain control wasn’t quite there and so there’s work for us to do.
“We’re still searching for a complete performance and we’re looking to improve, although there were real positives.”
Cowley switched to a 3-4-3 system against the Pirates and was pleased with how his side adapted to the change.
He said: “We haven’t got too many options in terms of personnel at the moment and we felt that it would be hard for Charlie Daniels to go again after playing so many games in quick succession.
“I haven’t got another left-back available, so we had to adapt and I’m not scared about formation changes.
“Callum Johnson played narrower, Marcus Harness was wider – which suits him – and Ryan Williams is willing to do whatever the team needs him to do.
“I thought the back three in particular were excellent and if you keep clean sheets, you normally win football matches.”