A moment of magic from Paddy Lacey secured Accrington all three points in an otherwise turgid encounter with Pompey.
The midfielder’s stunning second half strike was one of the few occasions when either side looked like scoring at a sunny Crown Ground.
There was a late surge for the visitors as they tried to secure a share of the spoils, but they were unable to find an equaliser.
Paul Cook made two changes from the side that beat Wycombe at Fratton Park the previous week.
Michael Smith came in for the injured Curtis Main up front, while Milan Lalkovic dropped to the bench to make way for Kyle Bennett on the left.
Pompey had a chance to break the deadlock with just three minutes on the clock when Carl Baker whipped in a dangerous cross from the right.
The ball found Gary Roberts standing unmarked at the far post, but the midfielder rolled his shot wide of the post.
Anyone who thought that would signal the start of an incident-packed half was to be left disappointed, however.
In fact, neither goalkeeper had to make a save of note, with both sides struggling to make an impact in the final third.
David Forde confidently dealt with a couple of Accrington crosses, while a Billy Kee free-kick failed to find its way through the wall.
The Blues did place the ball into some dangerous positions from out wide, but there was nobody in the box to make the most of them.
Meanwhile, the Stanley coaching staff were starting to grow frustrated by a couple of bewildering free-kick decisions that went the way of the visitors.
Pompey did wake everyone up with a decent opportunity on 33 minutes, but Michael Doyle – diving forward inside the box – could not quite guide Baker’s cross on target.
And the Blues then almost gifted Accrington the opener from a Sean McConville free-kick just before the break.
It was Christian Burgess who rose to meet it and inadvertently sent the ball against his own post before it was hurriedly scrambled clear.
Accrington Stanley 0
The match continued in the same turgid vein after the restart and a free-kick from Roberts failed to beat the first man.
But a rare moment of quality saw the hosts break the deadlock on 52 minutes, with Lacey hitting a stunning long-range strike that left Forde with no chance.
That certainly provided Accrington with a shot of confidence and Kee ran at the Blues back-line before hitting a tame shot straight at the keeper.
Pompey tried to mount a response and Aaron Chapman dealt with a couple of crosses, while Doyle hit a fierce drive over the crossbar.
Cook decided the time was right to make a change just past the hour mark, with Conor Chaplin replacing Danny Rose to provide a foil for Smith up front.
And another substitution soon followed, as Baker made way to give Kal Naismith a chance to impress against his former club
The third and final switch then came on 70 minutes, with Roberts coming off and Lalkovic the man charged with providing some attacking impetus.
He was soon involved in the action, but could not quite keep the ball in play after Enda Stevens’ cross had been flicked on by Smith.
Naismith then showcased a fine bit of skill to beat his man on the right, although his cross was slightly too high for Smith, who could only head over.
And Bennett turned his defender inside out on 82 minutes, sending in a fine delivery that a tightly-marked Naismith was unable to convert.
Pompey were applying some late pressure and a fizzing low Stevens cross was agonisingly out of reach for a number of black-shirted team-mates.
It was too little, too late, however, as the Blues’ impressive winning run ended with a whimper.
Accrington (4-2-3-1): Chapman; Vyner, Beckles, Pearson, Donacien; Lacey (Hewitt 80), Conneely (c); O’Sullivan (Boco 62), Clark, McConville; Kee
Goals: Lacey 52
Subs not used: Parish, Jones, Hughes, Eagles, Gornell
Pompey (4-2-3-1): Forde; Evans, T.Davies, Burgess, Stevens; Rose (Chaplin 63), Doyle (c); Baker (Naismith 67), Roberts (Lalkovic 70), Bennett; Smith
Subs not used: O’Brien, Clarke, Linganzi, Hunt
Referee: Mark Haywood
Attendance: 2,461 (806 Pompey fans)