In truth, this was a terribly boring match that failed to excite the fans, but I doubt many will care about the entertainment value given the importance of this victory today.
Steve Cotterill resisted the temptation to tinker with his defence and hey presto, the team don't concede! David Cotterill made his debut as Pompey played a 4-4-2 formation for the first time in recent memory.
But despite the more attacking lineup, this game produced few clear cut chances. David Nugent forced a great save from Luke Steele early on with an angled volley whilst the best move of the match, started by a great piece of skill from Cotterill, saw Dave Kitson fire wide.
Barnsley offered little in a first half that turned into a scrappy affair after that move from Pompey, although fans in the Fratton End held their collective breath as Danny Haynes' long range shot went narrowly wide when, for a moment, it looked like it would sail into the top corner.
Liam Lawrence had to be replaced by Aaron Mokoena before half-time, but the game didn't improve after the break and the referee hardly helped matters after waving away one of the most blatant handball offences you'll ever see and then by booking De Laet after the Barnsley player had tripped over his own foot.
The Pompey manager replaced Joel Ward with Kanu on the 71st minute, a decision that was greeted with boos by the home crowd as most people expected Kitson to be replaced as his performance was poor due to his reluctancy to shoot.
However, the decision was to be vindicated as the Nigerian added some much needed quality into the fame and made an impact just as the game was heading towards a bore draw.
Greg Halford lofted a free kick into the box and there was Kanu to glance the ball past Steele and into the back of the net.
A response was expected from the Tykes but if anything, Pompey should have made the result a certainty. Kitson's header was cleared off the line from a corner and then Hreidarsson headed the following corner straight into Steele's hands.
But Nugent really should have scored with just Steele to beat, but he could only put his shot wide and he beat the ground repeatedly in frustration having missed such an easy chance.
However, that didn't matter as the referee finally brought the dull game to an end and Pompey had secured back-to-back wins and had bagged another clean sheet.
The Barnsley fans probably left Fratton Park asking themselves why they had even bothered with the journey. Well, that's exactly how Pompey fans were feeling following the defeat at Oakwell earlier in the season, only that match was even worse.
We could complain about the quality of the match but we're in a period of the season where only results matter and this one has given Pompey a massive step to safety and an all-too-rare clean sheet.
The visit of Crystal Palace to Fratton Park on Tuesday promises to be a significant one. Dare I say it, but should the Eagles be beaten then surely Championship safety will be all but secured?
Pompey Player Ratings
Jamie Ashdown: 6 - Barely anything to do.
Ritchie De Laet: 7 - Impressive.
Ricardo Rocha: 6 - One dodgy backpass but otherwise solid.
Greg Halford: 6 - Dependable in the air.
Hermann Hreidarsson: 6 - Worked hard and stayed strong.
Liam Lawrence: 6 - Hopefully injury isn't too serious.
Joel Ward: 6 - Looked assured.
Hayden Mullins: 6 - Steady showing.
David Cotterill: 6 - Did OK on debut.
David Nugent: 5 - Had a couple of great chances to score.
Dave Kitson: 5 - Reluctant to shoot, lacks confidence.
Substitutes
Darryl Flahavan
Carl Dickinson
Ibrahima Sonko
Aaron Mokoena (Lawrence 40): 6 - Did a job.
Tom Kilbey
Nadir Ciftci
Kanu (Ward 71): 7 - Added some quality into the game.