Roberts, Linganzi and Whatmough on target.
A scintillating second half performance from Pompey saw them beat promotion rivals Carlisle at Brunton Park.
Goals from Gary Roberts, Amine Linganzi and Jack Whatmough ensured it was an enjoyable afternoon for the Blues in the north-west.
Neither side managed to take advantage of their chances in a first half that had plenty of talking points, but was short on quality.
It was the visitors who moved through the gears after the interval, however, and a fine strike from Roberts gave them a deserved lead.
Linganzi then opened his account for the club with another impressive strike to end Carlisle’s hopes of a comeback.
And Whatmough wrapped things up deep into stoppage-time with his first ever senior goal for the club.
Paul Cook made one change from the side that draw at Barnet the previous week.
Jamal Lowe dropped to the bench to make way for Carl Baker on the right hand side of Pompey’s attacking midfield trio.
The hosts had the ball in the net inside the first minute, but there were no celebrations from Jamie Proctor, as the linesman had long since raised his flag for offside.
Baker then tried his luck with a low shot at the other end, with Mark Gillespie getting down to beat the ball away.
Both sides were showing plenty of attacking intent, although the quality was lacking in the final third.
A slip from Christian Burgess almost let Reggie Lambe through on goal, but David Forde came charging from his area to reach the ball first.
United were then forced to make a change on 15 minutes, as a clash of heads saw Shaun Brisley replaced by Tom Miller.
There continued to be space for both sides to expose and Forde got down well to parry clear Nicky Adams’ angled drive.
The hosts then managed to work the ball across to the unmarked Miller on the right, only for Roberts to get a vital block in.
There was another piece of bad news for Carlisle on 36 minutes, however, when Michael Raynes picked up an injury and joined central defensive partner Brisley on the sidelines.
Pompey were looking more threatening as the first half progressed and Roberts curled a free-kick narrowly wide from just outside the box.
But the home support were outraged that their side were not awarded a penalty a few moments later.
Forde failed to collect a cross for the first time and in the ensuing scramble, the ball bounced up and hit Gareth Evans on the arm.
Referee Richard Clark ignored the desperate cries for a spot-kick to be awarded, agreeing with the Blues’ right-back that it had not been a deliberate offence.
And Pompey almost rubbed salt into the wounds by breaking the deadlock just before the interval.
Carlisle failed to deal with Evans’ low delivery into the box and the ball ricocheted into Eoin Doyle’s path, only for the striker to somehow clear the crossbar with the goal gaping.
Carlisle United 0
Whatever Cook said to his players at the break appeared to do the trick as the visitors came charging out of the blocks.
And they had three excellent chances to open the scoring within the first three minutes of the second half.
First Enda Stevens got free down the left and his low cross was almost diverted into his own net by Gary Liddle.
Roberts teed-up Eoin Doyle to slot the ball home from close-range a few seconds later, but the striker had strayed into an offside decision.
And another effort from the loanee then took a massive deflection and was looping in until a back-pedalling Gillespie managed to tip it over.
It was not all one-way traffic, though, and Proctor should have guided the ball on target when he met Luke Joyce’s pin-point cross.
Pompey were then back on the attack and when Gillespie fumbled Linganzi’s header, Kyle Bennett’s follow-up was blocked.
The action continued at a hectic pace as the action once again switched to the other end, with Forde getting down to brilliantly turn Lambe’s shot around the post.
Cook made a double substitution – and a change of system – on 72 minutes, as he went in search of a breakthrough.
Whatmough and Conor Chaplin replaced Baker and Bennett, with Pompey switching to a 3-5-2 formation.
And the move paid dividends within seconds, although it was a man already on the pitch who fired the visitors ahead.
It was a fine solo effort for ROBERTS, who burst clear through the centre and beat Gillespie with an exquisite finish.
The midfielder received a warm round of applause as he made way for Kal Naismith for the final 10 minutes.
And the points were then wrapped up late on, courtesy of a 25-yard strike from LINGANZI that arrowed into the bottom corner.
There was a mixture of delight and relief from the 1,209 travelling fans, who had plenty to cheer in the stands.
But they had even more to celebrate in stoppage-time when Naismith picked out WHATMOUGH to drill his first goal for the club into the bottom corner.
Carlisle (4-2-3-1): Gillespie; Liddle, Raynes (c) (McQueen 36), Brisley (Miller 15), Gillesphey; Joyce, Jones; O’Sullivan (Ibehre 60), Lambe, Adams; Proctor
Booked: O’Sullivan, Miller
Subs not used: Crocombe, Bailey, Devitt, Waring
Pompey (4-2-3-1): Forde; Evans, Burgess, Clarke, Stevens; Linganzi, M.Doyle (c); Baker (Whatmough 72), Roberts (Naismith 80), Bennett (Chaplin 72); E.Doyle
Goals: Roberts 73, Linganzi 86, Whatmough 90+2
Subs not used: O’Brien, Rose, Lowe, Hunt
Referee: Richard Clark
Attendance: 7,197 (1,209 Pompey fans)