Paddy Lane’s second-half strike proved the difference in a tightly-fought contest at Brunton Park.
The 22-year-old latched onto a perfectly weighted pass, before rolling beyond Harry Lewis to score what would prove to be the winner, on 62 minutes.
The opening exchanges saw both sides battle for possession in midfield as someone looked to forge the game’s first opportunity on goal.
Paddy Lane provided the first shot of the day, as his near post attempt forced Lewis into making the required stop.
Moments later, Jack Diamond pulled his effort wide from the edge of the area as we looked to catch the visitors on the break.
On 14 minutes, Pompey were awarded a free-kick 30-yards from Lewis’ goal. Marlon Pack stepped up to take and hammered well over Carlisle’s crossbar.
Soon after, we hurled a throw-in into the Portsmouth box, which was nodded on by a visiting defender into the path of Gibson, whose powerful shot flew over.
On 20 minutes, Carlisle looked to break the deadlock once again as Armstrong picked out Gibson, but his shot was deflected behind for a corner - which ultimately came to nothing.
Lane looked to lash the visitors into the lead moments later, after cutting inside from the right, he fired a left-footed effort on goal, but it landed the wrong side of Lewis’ far post.
Armstrong popped up with the next chance, forcing Will Norris into a near post save following a strong delivery from the right by Josh Vela.
On 29 minutes, Vela was shown the first yellow card of the game after catching Conor Shaughnessy late in front of the referee’s assistant.
Five minutes later, Pack whipped in a Pompey corner which finally found its way to Lowery, whose shot rattled against Carlisle’s post.
Sean Raggett provided the next chance of the contest but after taking aim from distance, his effort caused no issue to Harry Lewis.
The game entered a lull as the first-half came to a close with no further chances for either side.
Half-time: Carlisle United 0-0 Portsmouth
Pompey started the second-half brightly as Rafferty skipped inside beyond Mellish, forcing Lavelle to turn behind for a corner.
Myles Peart-Harris had a tremendous opportunity to open the scoring soon after as Ogilvie found him free inside the area, but the attacker was unable to make the needed connection.
The visitors continued their strong start to the second-half as Lang slipped a perfectly weighted ball into the path of Lane, but he fired wide from close range.
On 56 minutes, Lang received the ball on the edge of the box before firing over Carlisle’s crossbar from 25-yards out.
Lavelle made a much needed interception soon after, Pack looked to fire a low cross into the area but our skipper was equal to it, turning behind for a corner.
Pompey’s newly-introduced substitute Abu Kamara looked to have an instant impact on the contest as his mazy run forced Carlisle into another strong defensive clearance.
On 62 minutes, Paddy Lane opened the scoring for Portsmouth after sliding a coolly struck low effort beyond a helpless Harry Lewis.
Gibson looked to restore parity five minutes later after picking up the ball on the edge of the box, but his shot landed wide of Norris’ far post.
As we closed in on the final 10 minutes, Pack sent a looping free-kick into the area which was glanced on by Shaughnessy and came off the post, before Moxon lashed wide moments after making his return at Brunton Park.
The remainder of the game provided no clear chances for either team and despite Carlisle’s push for a leveller in stoppage time, it would end in defeat for Paul Simpson’s side.
Full-time: Carlisle United 0-1 Portsmouth
Carlisle United: N/A
Carlisle United: Vela
Carlisle United: Lewis, Back (75’ Grehan), Lavelle ©, Gibson (76’ Charters), Robinson (76’ Armer), Mellish, Barclay, Diamond (57’ Butterworth), Neal (76’ Maguire), Armstrong, Vela
Unused subs: Breeze, McCalmont
Portsmouth: Norris, Ogilvie, Pack, Bishop, Rafferty, Shaughnessy, Raggett, Lowery, Lane (85’ Sparkes), Peart-Harris (57’ Kamara), Lang (75’ Moxon)
Unused subs: Macey, Towler, Yengi, Martin
Referee: Martin Woods
Assistant Referee 1: Graeme Fyvie
Assistant Referee 2: Ivan Stankovic
Fourth Official: David McNamara
Attendance: 9053 (1848 away)