Colby Bishop bagged a brace as Pompey beat Port Vale at Fratton Park to remain top of the League One table.
They were not at their best before the break, but totally dominant after it, with Colby Bishop’s close-range finish opening the scoring.
And the prolific striker made sure of the points moments later, converting a penalty following a handball in the box.
John Mousinho made three changes from the side that dramatically beat Wycombe earlier in the week.
With Regan Poole and Alex Robertson both suspended, in came Sean Raggett and Ben Stevenson – the latter making his first league outing.
The other switch saw Christian Saydee return to the forward line, with Tino Anjorin dropping to the bench, where he was joined by a fit-again Kusini Yengi.
It was a breathless start to proceedings, with the action quickly switching from one end to the other in the opening stages.
And the visitors came close to taking the lead when Ben Garrity laid the ball off for Funso Ojo, who drilled a shot against the base of the post.
Jack Sparkes then tried to bend a free-kick inside the near post of Connor Ripley, but his effort flashed wide.
The full-back also swung in an excellent cross towards the back post, where an unmarked Paddy Lane could only nod wide.
There was soon a chance for the Valiants on 17 minutes after Pompey had failed to clear their lines, but James Plant fired wastefully into the side netting.
The rest of half was mostly a laboured affair, however, with the hosts struggling to find any kind of fluidity and not being able to advance into the final third.
Not that there was too much happening at the opposite end either, as the game became bogged down in midfield.
And with that attacking spark lacking, there was a sense of relief all round when the sides were able to regroup during the interval.
Half Time: Pompey 0 Port Vale 0
The Fratton faithful were searching for a response following the interval and Bishop had an early shot blocked.
And it was the Blues’ leading scorer who did break the deadlock on 53 minutes, much to the delight of most inside the ground.
Ripley could only get the slightest hand to a Sparkes cross and Joe Rafferty drilled the ball back into the mixer for BISHOP to turn home.
It soon got even better for the hosts, with Kofi Balmer falling to the turf and sticking out an arm to block Abu Kamara’s shot.
Referee Robert Madley pointed to the spot and BISHOP stepped up to send Ripley the wrong way and double the advantage.
Pompey sensed they could dish out further punishment and Garrity was well placed to clear a thumping Raggett header from the line.
When everyone finally had a chance to draw breath, Mousinho made a change by replacing Lane with Gavin Whyte.
The chances kept coming and a Raggett header was brilliantly saved at point-blank range by Ripley after Joe Morrell had swung in a cross.
Another substitution followed for the home side on 79 minutes, with Kamara making way for Terry Devlin.
The Northern Irishman had a chance to add a late gloss to the scoreline, but could not keep his shot down after being teed-up by Bishop.
But the Blues had already done enough ensure they head into the international break sitting at the summit and there was further reason to cheer when Yengi was brought on for a cameo.
Pompey (4-2-3-1): Norris; Rafferty, Raggett, Shaughnessy, Sparkes; Morrell (c), Stevenson; Lane (Whyte 70), Saydee (Yengi 90+1), Kamara (Devlin 79); Bishop
Goals: Bishop 53, 58 (pen)
Booked: Lane
Subs not used: Schofield, Swanson, Towler, Anjorin
Port Vale (3-4-2-1): Ripley; Lowe, Balmer, Smith (c); Sang (Massey 75), Ojo (Wilson 62), Arblaster, Grant (Devine 33); Chislett (Thomas 62), Plant; Garrity
Booked: Arblaster, Balmer, Lowe
Subs not used: Leutwiler, Cass, Walters
Referee: Robert Madley
Attendance: 17,837 (618 away fans)