Kenny Jackett lauded his Pompey players after overturning title-chasing Wigan.
The Fratton Park return of ex-boss Paul Cook turned sour as his side slipped to a 2-1 defeat in the south-coast rain.
Brett Pitman’s 20th goal of the season was joined by a second-half strike by Jamal Lowe to hand the hosts what proved to be an unassailable two-goal lead.
Latics substitute Will Griggs pulled one back in the 89th minute to create a tense finish.
But the Blues held out for an outstanding victory over a side which started the day as League One leaders.
Jackett said: ‘It’s a big win, fourth on the trot at a key time takes us onto 61 points which now with six games left, we are still in the hunt for fifth and sixth.
‘In terms of the game, I felt we did very well for an hour and then, for the last 30 minutes, Wigan got right on top of us.
‘The keeper (Luke McGee) made two key saves in that time. I know we battled away, but generally that period we dropped a little bit too deep, didn't do well enough on our break with the ball and it was all heart and guts which got us through.
‘Sometimes it’s needed, but if we also aspire to be a top team we have to learn from that.
‘I'm very pleased with the players, the effort and commitment, the heart, it was fantastic and keeps our season going.’