Five goal Blues fight back.
Pompey returned to winning ways in emphatic fashion as they crushed Barnet at Fratton Park.
But they had to fight from behind after John Akinde fired the visitors ahead from the penalty spot.
Gary Roberts teed-up Conor Chaplin to draw them level before the break and then got on the scoresheet himself early in the second half.
The Blues were rampant by this point and goals from Carl Baker, Milan Lalkovic and Danny Rose secured a comfortable victory.
Roberts should have added another in the midst of all that, only to see his penalty saved after Bira Dembele had been sent off for a foul on Chaplin.
Paul Cook made two changes from the side that were beaten at Accrington the previous week.
There were starts for Chaplin up front and Kal Naismith out wide, with Michael Smith and Kyle Bennett both dropping to the bench.
Pompey started brightly and Chaplin had a shot blocked by Curtis Weston before Enda Stevens’ cross had to be turned behind.
The duo were both involved in the next opening on 12 minutes, with a low Stevens delivery just out of reach for the Blues’ striker sliding in at the near post.
Gareth Evans then got free down the right, but his cross landed behind Baker, who could only hook over the crossbar.
Barnet were causing problems themselves, however, and David Forde charged from his area to beat Akinde to the ball.
Weston then got past Christian Burgess and into the Blues box, but the defender recovered well to avert the danger.
Tom Davies almost opened his Pompey account at the other end, as Baker’s cross hit him in the chest and landed safely in the arms of Bees keeper Josh Vickers.
But the centre-back conceded a penalty soon after, with referee Darren England deciding he had used his hand to clear Ryan Watson’s corner.
Akinde stepped up to take the spot-kick and although the former Blues striker’s shot was poor, it crept under Forde’s dive and into the net.
The same player might have doubled their advantage on 32 minutes, only to head Watson’s corner over from close range.
Instead it was the home fans celebrating as their side drew level, with Roberts acting as the magician and CHAPLIN the assassin.
The former did well to steal possession and then played a sumptuous pass through to the latter, who coolly slid the ball home.
Pompey had another chance before the break, but when Baker’s effort was blocked, an audacious over-head strike from Chaplin flew wide.
Barnet came flying out of the traps after the restart and it took a great challenge from Burgess to halt Jamal Campbell-Ryce’s surging run.
But the Blues should then have forged ahead, with Roberts somehow failing to connect with Stevens’ teasing low cross.
ROBERTS certainly made amends moments later, however, turning Michael Nelson and leaving him on the floor before hammering home.
And it soon got even better for the hosts, as BAKER collected the ball on the right, cut inside and curled an exquisite left-foot shot past Vickers’ grasp and into the net.
Pompey should have extended their lead further on 65 minutes when England awarded them a penalty.
Chaplin charged into the box and went down under Dembele’s challenge, with the official signalling that he had been tugged to the floor.
It got worse for the beleaguered Bees, as a red card was harshly produced and the defender had to trudge back to the dressing room.
Roberts stepped up to try to continue his prolific scoring spell, but Vickers flung himself to the left to beat the ball clear.
Cook made a double switch on 73 minutes, with Naismith and Chaplin receiving standing ovations as they were replaced by Lalkovic and Curtis Main.
And it was LALKOVIC who soon put the icing on the cake, receiving the ball on the edge of the box and neatly bending it right into the bottom corner.
Pompey refused to sit back and kept pouring forward in search of more goals to heap further misery on Barnet.
And the fifth did arrive in stoppage-time, as a neat passing move cut open the Bees defence before ROSE slotted home to cap a memorable afternoon on the south coast.
Pompey (4-2-3-1): Forde; Evans, T.Davies, Burgess, Stevens; Rose, Doyle (c); Baker (Bennett 80), Roberts, Naismith (Lalkovic 73); Chaplin (Main 73)
Goals: Chaplin 34, Roberts 50, Baker 56, Lalkovic 78, Rose 90+2
Booked: Chaplin, Roberts
Subs not used: O’Brien, Clarke, Linganzi, Smith
Barnet (4-3-3): Vickers; Vilhete, Nelson (c), Dembele, Johnson; Watson (Batt 55), Weston, Taylor; Campbell-Ryce (N’Gala 64), Akinde, Akpa Akpro (Gambin 55)
Goals: Akinde 27 (pen)
Sent off: Dembele
Booked: Watson, Batt
Subs not used: Stephens, Sesay, Kyei, Nicholls
Referee: Darren England
Attendance: 16,280 (275 away fans)