John Akinde was both the architect and the destroyer as he raised even more question marks over Pompey’s promotion credentials.
The striker failed to net during 11 Blues appearances in the second half of the 2012-13 campaign under Guy Whittingham.
Yet he was the difference at The Hive last night as Paul Cook’s side slipped to a disheartening 1-0 defeat.
The 26-year-old crumpled to the floor in the 41st minute under a challenge from behind from Adam Webster.
The contact was true, yet the ease in which the powerful striker fell to the floor incensed Pompey and their 1,330 travelling supporters.
Regardless, Akinde stepped up to clinically slam home his 12th goal of the season – and effectively settle the contest.
That breakthrough was no more than Martin Allen’s side deserved at that stage having dominated Pompey with embarrassing ease during the first half.
Cook’s men were found wanting alarmingly in the physical stakes and their game soon turned ragged in the face of such opposition.
It was all Pompey after the break, Jamie Stephens pulling off one excellent save from Adam McGurk’s header to keep their lead intact.
Inspired by Ben Davies’ surges down the right, it was wave upon wave of attacking pressure from the visitors, yet the goal would not arrive.
Substitute Kal Naismith fired a wonderful opportunity over the bar while there were appeals for a penalty when Mauro Vilhete fell on the ball while attempting a header.
Instead it was a sixth defeat of the league campaign for the Blues.
More concerningly, they find themselves in eighth spot – and outside the play-offs.
Cook made three changes to the side which so disappointingly drew at Yeovil at the weekend.
The groin injury to Gareth Evans was an alteration enforced, while Christian Burgess was missing following his Huish Park red card.
That meant a return to the side for Matt Clarke, partnering Adam Webster at the heart of Pompey’s defence.
As for Evans, he was replaced by Adam McGurk on the right of the Blues’ attacking midfield three, marking his first league start since November at Wycombe.
The final change was Marc McNulty getting the nod over Michael Smith to feature as Cook’s lone striker.
McNulty had been dropped to the bench for the previous two games, but returned to the starting line-up in place of the loanee from Swindon.
There was no place among the substitutes for Ben Tollitt, who played for 49 minutes of the 1-1 draw at Yeovil after coming off the bench.
However, Danny Hollands was back following his broken leg, while Conor Chaplin had recovered from the ankle injury which kept him out of the Glovers’ trip.
Meanwhile, Allen rang the changes to the side which lost 2-1 against AFC Wimbledon at the weekend, making four alterations.
Tom Champion, Sam Muggleton, Matt Stevens and Mark Randall all came into a side which also included ex-Pompey pair Akinde and Bondz N’Gala.
In the opening seconds of the match, Ryan Fulton was called upon to challenge Akinde for a high ball inside the penalty area.
The keeper failed to hold the ball, although the fact the striker had clattered into him as he attempted to do so warranted the referee to award the Blues a free-kick.
At the other end, Kyle Bennett seized upon a bouncing ball 20-yards from goal to rifle a right-foot shot which flashed past the right-hand post.
In the fourth minute Clarke tripped Akinde and Andy Yiadom fired the resulting free-kick against the wall before muted appeals for a foul inside the box on Stevens.
Cook was forced into a substitution on seven minutes when Gary Roberts, who had been a doubt in the build-up, was replaced by Kal Naismith.
The reshuffle saw Naismith go on the left of the attacking three, with Bennett switching to the centre behind striker McNulty.
Clarke’s tackle on Akinde earned the hosts a corner down the right on 19 minutes and Sam Muggleton’s delivery almost opened the scoring.
His left-footed flag kick missed everyone and Fulton was forced to parry at his near post before scooping up the loose ball with bodies in front of him.
Champion earned the first booking of the game following a challenge on McGurk in the centre of the pitch on 21 minutes.
Moments later Pompey won their first corner, taken from Ben Davies down the right, but it came to nothing.
Barnet’s hard-working and no-shirking approach was troubling Cook’s side and when Stevens attempted a flying overhead kick he made sufficient contact to send the ball past the far post.
A ball over the top then saw Akinde get between Webster and Clarke, but the former applied enough pressure to disrupt the striker’s shot, which subsequently lacked any power.
The visitors were struggling and when Curtis Weston beat Davies to the ball he drove in a cross-cum-shot which prompted a diving stop from Fulton.
In a rare Blues attack on 32 minutes, Davies flung in a cross from the right and Naismith missed his header at the near post when a touch could have broken the deadlock.
The Scottish winger did, however, fire in the visitors’ first shot on target when in the 37th minute he crashed a swerving left-foot effort which Jamie Stephens collected with a little difficulty.
The Bees responded with Mark Randall’s shot from 20-yards which Fulton instinctively pushed out for a corner in a superb moment of goalkeeping.
Yet on 41 minutes the hosts did take the lead after Webster was adjudged to have fouled Akinde from behind inside the box.
Akinde took the penalty, sending Fulton the wrong way with a confident finish into the bottom left-hand corner.
As a tough half for Cook’s men drew to a close, the impressive Yiadom found a way down the right but, after taking his time to pick out a player, the cross eluded all his team-mates.
Pompey were sent back out early at the interval with no substitutions and clearly words had been exchanged.
In the 50th minute a cross from Davies down the right was met with a McGurk header which was brilliantly tipped over the bar by Stephens.
Already it was far brighter from Cook’s side, who raised the tempo and finally began to put Allen’s men under sustained pressure,
There was another Blues change when, on 59 minutes, Close made way for Smith.
Immediately McNulty cut the ball back from the left where the unmarked Naismith fired a first-time shot over the bar from 10-yards out when he should have done far better.
Then a Naismith free-kick from the left was met with a Clarke header at the far post, with the defender directed the ball straight at the keeper.
On 69 minutes there were calls from the Fratton faithful for a penalty when Mauro Vilhete fell on the ball inside the area, but nothing was given.
Cook made his third and final substitution on 77 minutes with Chaplin coming on for McNulty.
Still Pompey pushed, but the equaliser wouldn’t arrive as Barnet safely saw home their three points.