The rout began after Michael Morrison's blatant handball gifted Pompey a penalty in the 10th minute and Liam Lawrence showed previous Pompey players how to take a penalty by slotting it into the corner of the net having sent Conrad Logan the wrong way.
Leicester got back into it and Pompey's defensive frailties were exposed when Andy King found the net, only for the offside flag to go up to the relief of all Portsmouth fans.
The game was fairly even with both defences presenting opportunities for their opposition. Mokoena volleyed over from close range and Lawrence forced a superb save from Logan with his ferocious angled drive from outside the box.
The hosts also had Brown go close with a shot that went wide but Martyn Waghorn came close to equalising for Leicester as his long range effort went narrowly wide.
But just as Paulo Sousa's side had weathered the storm, they were reduced to ten men as Vitor was sent off for wrestling Nugent to the ground when he was rushing through on goal.
The decision may be viewed as harsh given that there were other defenders around him but I'd say that decision was karma for all the decisions given against us on Tuesday.
Up stepped Liam Lawrence to smash in a second goal as Bruno Berner deflected his fierce indirect free kick into the net to double Pompey's lead on the half hour.
The game remained at 2-0 after the first half and the second half started slowly until Carl Dickinson's audacious attempt to lob Logan from near the halfway line resulted in the ball hitting the crossbar. If that had gone in you could have cancelled the "goal of the season" competition there and then!
It didn't take too much longer for Pompey to score the third, however, as Kitson's shot was saved by Logan and the Leicester 'keeper then stopped Nugent's initial follow up but couldn't stop his second attempt from finding the net, giving Nuge his first league goal of the season.
The Foxes crumbled after that and Pompey added a fourth straight from the restart as Nugent won the ball back straight from kick-off and set up Kitson who chipped the ball over Logan for his second goal of the season.
Leicester did pull one back as Steve Howard shot past Ashdown after some confusion in the box but the rout wasn't over as Kanu and Ciftci came on and continued to open up the Foxes.
But it was Kitson who scored the fifth after taking advantage of Leicester's awful defending as he was presented with an easy chance from close range which he gratefully scored.
A rocking home crowd watched on as Kanu continued to make a mockery of the Leicester players but the icing on the cake was provided by Brown who seemed to believe he was Lionel Messi for a moment as he danced his way through three yellow shirts before round Logan and slotting into an empty net.
It was a stunning way to cap a memorable night at Fratton Park as the Leicester bogey was buried in some style. The critics will say that Leicester were poor and gifted us the two goal lead and that they had to play an hour of the match with ten men, but given our position all that mattered was the result.
Besides, a poor team still wouldn't have managed to put six goals past Leicester regardless of the man advantage and the win should give everyone who played in the game a huge boost in confidence.
We need to build on this outstanding win now by beating Bristol City on Tuesday, preferably in the same manner as last night if we want to prove that the performance wasn't simply just a flash in the pan.
Until then, we should just sit back and look at the Championship table because it's good to see that Portsmouth aren't bottom any more!
Pompey Player Ratings
Jamie Ashdown: 6 - Nothing to do but could have distributed the ball quicker.
Joel Ward: 8 - Starting to establish himself in the side despite a couple of awkward moments early on.
Aaron Mokoena: 7 - Did well but found Howard a handful.
Ricardo Rocha: 7 - Did the basics well.
Carl Dickinson: 8 - Best performance so far - if only his effort went in!
Liam Lawrence: 9 - Got the ball rolling with two goals and was a constant threat all game.
Hayden Mullins: 8 - Never stopped working, shame he went off with an injury.
Michael Brown: 8 - Super goal capped excellent performance.
John Utaka: 7 - Had the better of the Leicester right back and even gave some effort!
David Nugent: 9 - Got the goal his effort deserved and always looked dangerous.
Dave Kitson: 9 - Showed his goalscoring instinct and was too difficult for Leicester to handle.
Substitutes
Darryl Flahavan
Ibrahima Sonko (Rocha 82): N/A - Nullified Howard for the last minutes.
Nadir Ciftci (Mullins 75): N/A - Tested Logan with angled drive.
Kanu (Nugent 78): N/A - Created space and picked his passes like it was an exhibition match.