Naismith and Roberts on target.
Pompey moved another step closer to promotion with a 2-0 victory at Hartlepool.
A goal in either half from Kal Naismith and Gary Roberts ensured the Blues registered a fifth win from their past six games.
There were chances at either end of the pitch in an entertaining contest in the north-east, with both sides striking the woodwork.
Paul Cook made three changes from the side that beat Newport on home soil the previous week.
Christian Burgess returned from a one-match to replace Tom Davies at the heart of defence.
And with the injured duo of Carl Baker (hamstring) and Eoin Doyle (groin) both missing, there were returns for Jamal Lowe and Noel Hunt.
There was a breathless start to proceedings, with the ball quickly switching from one end of the pitch to the other.
It was the visitors who were first to threaten with a Naismith corner that was not properly dealt with, forcing Joe Fryer to leave his line and punch clear.
But Hartlepool then broke quickly following another Pompey set-piece, only for Lewis Alessandra’s surging run to eventually break down.
The ball soon found its way out to Liam Donnelly on the right and his cross was glanced wide by Nathan Thomas.
And the action then switched to the opposite end, as Kyle Bennett saw his effort blocked before Naismith dived to meet Enda Stevens’ delivery and send the ball flying narrowly past the post.
But the Blues did break the deadlock on 17 minutes when Stevens found NAISMITH in acres of space to send a smart volley into the back of the net.
The advantage might have been doubled soon after, but a sliding Hunt could not quite reach Gareth Evans’ low cross.
Hunt then tried a snap-shot from the edge of the box, although the ball flew comfortably into Fryer’s arms.
It was the hosts who soon began to dominate possession as they searched for an equaliser without being able to test David Forde.
There were a few shots blocked by the Blues back-line, but Hartlepool were largely guilty of looking for the perfect final pass instead of trying their luck.
The display of one additional minute for stoppages seemed to signal an incident-free end to the first half.
But the players remained on the pitch for a lot longer, with Hunt landing awkwardly after challenging for the ball.
He was treated on the pitch before eventually being stretched down the tunnel and replaced by Roberts.
Hartlepool United 0
Naismith was now leading the line for Pompey, but it was still Hartlepool looking the most likely side to score.
And, shortly after Forde had commandingly punched clear a cross, they had their best chance yet to draw level.
It was a cleanly-struck effort from Thomas that curled around the keeper’s grasp and cannoned back off the post, with Rhys Oates’ follow-up blocked by Matt Clarke.
But Roberts then missed a great opportunity to double the Blues’ advantage, diving to meet Stevens’ cross, but sending the ball over from close range.
The substitute made up for that miss, however, by finding the target on the hour mark and sparking wild scenes of celebration in the away end.
Naismith was the provider, staying calm when his initial effort was cut out and unselfishly slipping a pass through to ROBERTS, who slammed the ball into the roof of the net from a few yards out.
And Naismith almost had another goal of his own soon after, surging forward and sending a low shot against the base of the post.
Conor Chaplin replaced Lowe for the closing stages, as Cook decided to reintroduce a more traditional striker.
There was even a late cameo for Nicke Kabamba, as Pompey saw out the final few moments with ease to secure the points.
Hartlepool (4-1-4-1): Fryer; Donnelly (Magnay 90+2), Walker, Harrison, Deverdics; Featherstone (c); Oates (Rodney 75), Woods, Alessandra, Thomas; Amond
Subs not used: Dudzinski, Bates, Hawkins, Richardson, Rooney
Pompey (4-2-3-1): Forde; Evans, Burgess, Clarke, Stevens; Rose, M.Doyle (c); Lowe (Chaplin 80), Naismith (Kabamba 90), Bennett; Hunt (Roberts 45+5)
Goals: Naismith 17, Roberts 60
Subs not used: O’Brien, Talbot, Whatmough, Linganzi
Referee: Mark Brown
Attendance: 4,500 (977 Pompey fans)