Pompey booked their place in the FA Cup second round with a 2-1 victory at Harrogate Town amid power cuts that forced kick-off to be delayed.
Electrical faults caused the game to be pushed back by 55 minutes and there was almost a major shock against the National League outfit at Wetherby Road.
The Blues fell behind in the early stages when Mark Beck nodded home but goals from Brandon Haunstrup and Ronan Curtis set up a home tie with Altrincham in the second stage of the competition.
Yet there was bad news for the visitors as skipper Tom Naylor and Sean Raggett both limped off with injuries on the 3G surface.
Kenny Jackett made three changes from last week's 4-1 win over Southend.
Craig MacGillivray was fit to face his former side and replaced Alex Bass in goal.
Haunstrup came in for hamstring-victim Ross McCrorie, while Gareth Evans started ahead of Ellis Harrison – who was absent from the match-day squad.
Pompey made a nightmare start when falling behind after just seven minutes.
Jack Muldoon headed back across goal after Warren Burrell’s initial header from George Smith's free-kick and Beck was there to pounce from close range.
The Blues were back level 10 minutes later, however, when Haunstrup netted his maiden Pompey goal on his 50th appearance in style.
The Waterlooville lad played a fine one-two with Ben Close and then Ryan Williams before curling home a left-footed shot from just outside the area.
It was a frantic opening to the tie on the artificial surface which the visitors were taking time to acclimatise to.
On 21 minutes Town skipper Josh Falkingham cracked a ferocious effort but hit his team-mate Beck on the way towards goal.
And three minutes later Christian Burgess misjudged a bouncing ball that allowed Muldoon in on goal but he shot wide.
Then Close went up the other end to test home keeper James Belshaw, who made a decent stop to his right.
The 3G pitch had an impact on Jackett's troops, with both Naylor and Raggett limping off injured and replaced by Anton Walkes and Paul Downing inside 32 minutes.
But Pompey didn’t let it affect them and Curtis gave them the lead four minute before the interval when his dipping 30-yard effort superbly found the back of the net.
The game settled down somewhat in the second half, with Williams’ cross-cum-shot in the 54th minute denied by Belshaw.
Then the home stopper produced two good saves to thwart Marquis at the back stick when Gareth Evans stood up a cross.
Town began to get on the front foot as the game wore on. Substitute George Thomson almost made an instant impact when his snap-shot left MacGillivray rooted to the sport but the ball luckily went the wrong side of the post.
And Beck was proving a potent aerial threat, twice going close from Thomson corners.
But Pompey almost wrapped up the victory with 10 minutes remaining when Lee Brown burst forward but his cross-cum-shot clipped the far post.
And Jackett’s men held on for victory and will meet another non-league side in Altrincham in the second round at the end of the month.