Brett Pitman's twelfth goal of the season was enough to see off Southend on a dramatic afternoon at Fratton Park.
An unchanged side could have taken the lead after just five minutes when Pitman somehow missed the target from close range following a superb cross from Matt Clarke from the left.
Southend squandered a good chance of their own when some poor Pompey defending led to some pinball in the box only for Nile Ranger to miss the first of his two excellent opportunities during the game and fire the ball wide from six yards.
Theo Robinson had tested Luke McGee prior to that with a curling effort but neither goalkeeper had much to do in a first half which was becoming increasingly frustrating because of sloppy passing from both teams.
However, the crowd soon livened up when the game entered stoppage time.
Simon Cox's effort was brilliantly headed off the line by Danny Rose and the follow-up was blocked by a combination of Christian Burgess and Matt Clarke. One of the Southend players ran to assistant referee John Farries claiming handball and he agreed, as the man in charge pointed to the spot.
That decision drew an anger from the home crowd not seen and heard for years. Loud "Wanker! Wanker! Wanker!" chants were aimed at the officials in a rage that hasn't been repeated since Jermain Defoe was sent off for Tottenham at Fratton Park back in 2009.
Replays have since shown the decision to be incorrect as the ball hit Clarke in the chest at some speed but it stood and up stepped Nile Ranger to take the spot kick with over 17,000 hostile Pompey fans piling on the pressure.
Personally, I had a feeling he was going to miss and it seems others thought he would bottle it too and that turned out to be the case as he sent the ball sailing over the bar and into a jubilant Fratton End as the half came to a close.
That incident certainly changed the mentality of the players as Matty Kennedy was introduced from the bench for the lacklustre Kyle Bennett. The substitute soon made his mark as his cross into the box was headed in by Pitman to give the hosts the lead.
Southend attempted to muster attacks on goal but they were snuffed out by the back four and when they began getting desperate by pumping high balls into the box, they were met by the heads of either Burgess, Clarke or Ollie Hawkins who impressed as a centre back once again.
Those Shrimpers attacks gave Pompey a few opportunities to counter but the final ball on the break wasn't good enough to seriously test the Southend goalkeeper.
It didn't matter in the end as Pompey saw out the pressure at the end of the game to claim their third straight win in all competitions.
The victory was deserved based on the second half performance after an even first 45 minutes. Obviously the main talking point will be the penalty decision and the justice which followed and the fans should be commended for making the atmosphere as toxic as possible for the opposition.
It was like the good old days of Pompey's early seasons in the Premier League where the intimidating Fratton Park crowd became famous for unsettling visiting teams and were worth a fair few points every season. Hopefully that will continue for the visit of our friends from Devon on Saturday!
Pitman was given the man of the match award for his goal which was another one made of nothing and that skill is priceless at any level of football but there were more deserving candidates for that award.
Clarke performed excellently at left back by doing his defensive duties and showing his skill on the ball to take it forward and create opportunities. It seems like his silky goal at Fratton Park during the Checkatrade Trophy game against Crawley wasn't out of character and he is going to be difficult to keep hold of when January arrives.
Rose was also excellent for the second game running. His block on the goal line was crucial but his overall contribution to the team with his midfield performance was key to keeping Pompey ticking. Ben Close also proved he is capable of playing at League One level with his showing, so Stuart O'Keefe will have to wait a while to return to the side.
Yesterday's victory puts Portsmouth in 10th place in League One amongst a cluster of clubs on 26 points and now just two away from the play-off places.
It would be jumping the gun to suggest Pompey could sustain a promotion challenge at the moment, especially as Kenny Jackett's men have lost the majority of the teams they've played who are currently above them in the league.
But it's something to build on going into another important match at Peterborough on Tuesday night.
Pompey Player Ratings
Luke McGee: 7 - Confident showing despite not having too much to do overall.
Gareth Evans: 7 - Dependable.
Christian Burgess: 7 - Typically solid showing.
Ollie Hawkins: 7 - Continues to impress in his unfamiliar role.
Matt Clarke: 8 - Top class.
Danny Rose: 8 - Back to his best.
Ben Close: 7 - Continuing to silence his doubters.
Jamal Lowe: 6 - Worked hard.
Kal Naimsith: 6 - Held the ball up nicely when he had to.
Kyle Bennett: 5 - Not his day.
Brett Pitman: 7 - Scored the vital goal.
Substitutes
Alex Bass
Nathan Thompson (Lowe 86): N/A - Sub to shore up the defence.
Dion Donahue
Stuart O'Keefe
Matty Kennedy (Bennett 46): 7 - Made the desired impact.
Conor Chaplin
Curtis Main