The victory means the Town now sit five points clear at the top of Sky Bet League One having stretched their unbeaten run in the division to 17 matches - while extending their record without defeat at home to 19 games dating back to last March.
Even the wintery showers throughout the match could not deter the Hatters' home form, the team now snowballing their way to what could be a stunning season in the third tier.
James Collins bagged a brace to take his tally up to 16 for the season and George Moncur stole the hearts of Luton fans, scoring his first goal in orange since his move from Barnsley - a ferocious late free-kick to send every Hatter home smiling.
Mick Harford named an unchanged starting XI from the side that beat Southend United on Saturday and Pompey’s newest addition, Omar Bogle, began the match on the bench.
The second half provided a real top of the table clash after the first 45 belonged to Luton, who could have been out of sight at the midway point after a dominant display.
Kazenga LuaLua had the first of many chances, making the most of the conditions with some neat footwork to twist and slip away from his marker. His low cross was cleared, but Jack Stacey collected on the edge of the area and powered his strike well over into the Kenilworth Road end.
LuaLua looked lively moments later with another decent cross where Collins went for the spectacular. Unfortunatley though, his flailing leg could not send the ball goalward in an awkward attempt at a bicycle kick.
A minute later it was the Hatters again who pounced on a Pompey mistake, this time James Justin fizzing a shot at goal that Craig MacGillivray had to be ready to deal with, parrying away to Berry, who couldn’t control the rebound.
It was on 20 minutes when Justin picked the ball up on the left and found LuaLua outside the area. His smart flick and turn pulled another fine stop from MacGillivray down to his right, as the visitors struggled to soak up the Luton pressure.
Berry got involved in the avalanche of Luton chances too, curling his shot wide of the left post. Stacey also teed up the midfielder a little later on, creating space on the wing and finding Berry in the area who put a glancing header just wide, but close enough to have MacGillivray sprawling to his right to avert the danger.
The work rate of this Hatters side in the first 45 minutes was remarkable, Collins heading a Pompey cross clear in his own area and chasing it down, blocking the last defender's attempted ball forward to create another chance for the hosts, but Shinnie couldn't get a shot away.
McCormack’s low drive couldn’t find its way into the back of the net, as all that was missing from the Hatters at this point was a goal. LuaLua took a heavy touch from a superb through pass from Stacey and couldn’t get his shot past the keeper.
The goal arrived eventually though, a terrific team effort involving five players beginning with McCormack. The midfielder won a challenge midway inside his own half, which allowed Mpanzu time to thread the ball wide to Stacey.
The move then made its way to LuaLua after a driving run from Stacey gave the forward the chance to find Collins, who received a well weighted pass, and ended the passage of play with a tremendous finish which nestled sweetly in the bottom right corner.
But the Hatters weren’t done. The onslaught continued and Portsmouth just couldn’t deal with the home side’s dominance. Gareth Evans, with the only shot of the half for the Blues, summed up their miserable start at Kenilworth Road, slipping whilst hitting his shot onto the roof of the Oak Road.
On the stroke of half time, Collins nearly notched a second when a poor back pass had him chasing the ball down once more. His strike rebounded off the keeper to the feet of LuaLua, who was swarmed by blue shirts and could not force the ball towards the goal. The referee then called time and gave Portsmouth a chance to regroup.
And they did just that, taking advantage of a slow Luton start, dominating the next 25 minutes. It was the polar opposite of what the first half had seen, with Bogle - signed on loan from Birmingham on Monday - and midfielder Dion Donohue on for Brett Pitman and Evans. Donohue with the first chance, a low effort which stung the palms of Shea, who held onto it well considering the pace it had gained on the icy pitch.
The introduction of Bogle certainly bolstered the attacking line, creating the chance for Curtis, who levelled in what can only be described as Pompey’s first real chance of the match, side footing home in the exact some corner as Collins’ strike in the first half.
Shea was called into action just after, keeping the Hatters in the match that had turned so quickly in the favour of Portsmouth. A swift counter attack found its way to Morris on the right, who forced a delightful save from the Luton keeper - reaching highest to tip the ball over the bar.
Curtis was on the prowl once more and reacted quickest in the Luton penalty again, this time Shea saving well at his near post for another vital stop.
It wasn’t until the 71st minute that Justin had the Hatters' first chance of the second half. LuaLua picked the defender out with a firm square ball, and he cut inside upon receiving it and bent it in search of the top corner, only for MacGillivray to spoil what would have been a belter.
The Hatters began to play some better stuff as the minutes ticked into the final quarter of the match but were still suffering from a shock 25-minute spell which showcased why Pompey have the best away record in the division. But the Town were given a lifeline in the form of a penalty.
LuaLua was clearly tripped in the area to allow Collins the chance of grabbing his 16th goal of the season. He duly obliged and scored the spot kick, but back came the visitors.
Literally within a minute, and it was the half-time substitute and new-boy Bogle who took advantage of a Luton mix-up, tapping the ball home from close range.
But the Hatters had a new boy of their own in Moncur. His introduction in the 80th minute proved to be pivotal when the Town won a free-kick on the edge of the area four minutes from time.
Up stepped Moncur - the hopes of a sold-out Kenilworth Road on his shoulders - and he delivered, coolly curling his free-kick around the wall and into the far right of the goal to cue pandemonium in the home end and affirm himself a new Hatters hero.
A nervy four minutes of stoppage time were endured by the home defence, but they held on to earn a crucial three points that keeps the Hatters at the top of Sky Bet League One in front of the biggest crowd of the season at the Kenny.
The hard work continues though as the side now turn their attention to Shrewsbury away on Saturday...once the final 48 hours of the transfer window have been negotiated!
TOWN: Shea, Stacey, Pearson, Bradley (c), Justin, McCormack, Mpanzu, Shinnie (Sheehan 88), Berry (Potts 73), Collins, LuaLua (Moncur 80). Subs: Jones, Read, Tomlinson, Isted.
Goals: Collins 39, 77 (pen), Moncur 86
POMPEY: MacGillivray, Brown, Whatmough, Clarke, Walkes, Naylor, Evans (Donohue 46), Lowe, Curtis, Pitman (Bogle 46), Morris. Subs: Bass (GK), Burgess, Haunstrup, May, Donohue, Dennis.
Yellows: Donohue, Naylor
Goals: Curtis 52, Bogle 79
REFEREE: Simon Hooper
ATT: 10,078 (1,033 away)
