David Connolly was the hero as Pompey kept up their flying form with a 1-0 victory over promotion-chasing Tranmere.
Connolly’s effort early in the second half made the difference at Fratton Park, as the Blues grabbed their third home win on the bounce.
That also extends their unbeaten home run to five matches spanning two months.
The result closes to the gap to League One safety to just three points with four games remaining - although there is the 10-point deduction to still consider.
Connolly will be delighted to have grabbed his fifth goal since joining the club, after missing a great first-half chance.
But Pompey were good value for the win with Rovers having their moments, but the Blues have the greater number of efforts.
Plenty of those arrived in the first 45 minutes, and they became increasingly clear-cut as the half wore on.
Jed Wallace fired over from 25 yards after eight minutes before Gabor Gyepes headed just over the top from a corner.
Ash Taylor then nearly poked Wallace’s cross into his own net as the home side had the better of it.
Tranmere were having their spells, though, with Simon Eastwood continuing his fine form as he tipped over Abdulai Bell-Baggie’s effort.
Pompey should have had the breakthrough seven minutes before the break when Connolly wasted a gilt-edged chance.
Patrick Agyemang nodded into the striker’s path, but he uncharacteristically blazed his shot over with the goal at his mercy.
Rovers started the second-half brightly, but it was Pompey who made the breakthrough eight minutes after the break.
The excellent Yassin Moutaouakil was the architect as he reached the byline and crossed for Connolly, who couldn’t miss from a yard out.
Rovers pushed late on as they looked for the leveller that would keep their promotion hunt on track.
But it was Ertl who nearly added to the goals when his 25-yard blast was well saved by Williams.
Pompey then held on to get the win and pick up another morale-boosting three points - and make it just a single defeat in their past eight games.
POMPEY 1 (Connolly 53)
Pompey: Eastwood, Moutaouakil, Gyepes, Sodje (Rocha 81), Cooper, Maloney (Walker 72), Ertl, Racon, Wallace, Connolly, Agyemang (Akinde 78). Subs: Smith, Butler, Webster, Harris.
Tranmere: Fon Williams, Holmes, Taylor, Palmer, Bakayogo (Stockton 61), Gibson, Power, Bell-Baggie, Sidibe, Akpa-Akpro, Sean McGinty. Subs: Goodison, McGurk, Harrison, Kay, O’Halloran, Mooney.
Referee: Andy Madley (Wakefield).