Jatta, recently signed from AFC Portchester, grabbed the only goal 22 minutes from time to wrap up a 1-0 win for Tom Grice's men.
In five previous league matches with fellow PO postcode sides, US Portsmouth had failed to pick up a point.
But after struggles and defeats against Baffins Milton Rovers, Moneyfields, Horndean, Portchester and Fareham, USP finally came away from a PO postcode derby battle with victory.
It also secured successive wins for US Portsmouth for the first time this season and player-assistant manager Tom Jeffes was understandably delighted.
Denver Hume: Portsmouth's expensive forgotten man and why former Sunderland defender really could be one for the future
'Real driving force... lion-hearted display... classy presence' - Neil Allen's Portsmouth ratings from 3-0 Carabao Cup win at Cardiff
'We wanted to show him a bit of love' - Portsmouth-based Spurs fans' terrific gesture to ensure Dane Scarlett feels at home on the south-coast
League One latest: Portsmouth linked duo set for Oxford United and Lincoln moves, Southampton prospect joins Blues rivals as Ipswich land former Blackpool and Derby veteran
'We’ve got a real problem': Portsmouth boss reveals headache after career first at Cardiff
He said: ‘We’ve been banging on and drumming in our systems now how we want to play and what we want to do. I think yesterday (against Fareham) was the first time we’ve done it for 90 minutes.
‘We’ve always joked if the season was based on 45 minutes we’d probably be in the top two or three, but unfortunately it’s not. On the flip side, if it was played over 90 minutes then we’d be in the bottom two or three given how we’ve performed in some second halves.
‘You know what it’s like when you’re playing the teams in and around you, it does have a bit more impetus on it.
‘It was nice because we’ve lost all of the games to the other teams around u from an area perspective - it was a nice result - especially as we lost 6-1 at their place.
‘Again, we felt we were the better team in the first half, we came in a bit disappointed to be at 1-1. It was nice to put that right yesterday, to be fair.’
It was quite the turnaround for US Portsmouth, who were on the end of a 6-1 hammering in the reverse fixture at Fareham in September.
Jatta was the man to put that right, striking on 68 minutes to make it two goals in three games since moving to the Victory Stadium.
But Reds boss Pete Stiles was far from impressed with his side's display.
He said: ‘We weren’t at the races at all. My two centre-halves are probably the only two players who come out with any credit. We were just well below-par - that’s one point we’ve taken out of a possible nine. Looking now, we’re seven points adrift of the top-six and that’s why.
‘There are games there, I don’t expect to win every game, but I do expect the lands to perform better than that.’