Gary Roberts was spot on to again seal victory for Pompey from the penalty spot at Exeter.
Roberts’ spot-kick gave Paul Cook’s side a 1-0 win at St James Park and two league wins on the bounce.
The Blues’ talisman did the business against Colchester last week from 12 yards - and it was the same again against the Grecians.
It looked as if the chances being created by Pompey would amount to nothing as they had opportunities without overly working Exeter keeper Bobby Olejnik.
The introduction of Conor Chaplin and Noel Hunt in the second half again pepped up their side, however.
And the goal came late on to give Cook’s men their first away maximum of the campaign.
The stats at the interval showed it was 10 shots to one in Pompey’s favour.
The Blues began to rack up their chances with both Curtis Main and Gary Roberts having 20 yarders which failed to find the back of the net.
Carl Baker then cut dangerously into the box but dragged his shot into the side netting.
Christian Burgess had the best chance of the half after 26 minutes when he rose on his own from Roberts’ free-kick but nodded his header wide.
A great hit from Danny Rose was on its way seconds later until it smacked Troy Brown in the head and left the defender prostrate on the turf.
Exeter’s soul effort in the first half came as Liam McAlinden failed to get enough purchase on his shot when well placed and David Forde easily gathered.
The second half began with Pompey having the play without the penetration.
That changed on 56 minutes when Milan Lalkovic put in a beautiful cross which was headed agonisingly wide by Main.
Conor Chaplin’s introduction then lifted Pompey as he blazed down the right and arrowed a shot inches wide with Ethan Ampadu on the back foot.
Then Christian Burgess had to produce an important clearance to deny Joel Grant a certain goal from Ollie Watkins’ cross.
The game had opened up after Chaplin’s introduction and Pompey move to using two strikers.
And Noel Hunt so nearly guided home Chaplin’s cross-shot moments after his introduction, but Olejnik somehow kept it out.
The goal the arrived with five minutes left when sub Kal Naismith got away from Pierce Sweeney and was bundled over.
It was that man Roberts who held his nerve to blast his spot-kick home and celebrate in front of the 1,215 travelling Pompey fans.
There was a nervy five minutes of additional time for Cook’s men, but Pompey weathered the pressure to collect the three points.