Matt Tubbs' sixth goal of the season secured a 1-0 win for Portsmouth at Newport to keep the visitors among the Sky Bet League Two pace-setters.
Tubbs, fresh from scoring a hat-trick against Cambridge last week, got the only goal of the game when he calmly slotted home Kyle Bennett's pass in first-half stoppage time.
There were some encouraging signs for struggling Newport, with loan signing Tommy O'Sullivan impressing, but they remain firmly rooted to the foot of the table after another defeat.
County thought they had taken the lead in the 31st minute when striker Lenell John-Lewis pounced on a poor Christian Burgess header to head home, but the goal was disallowed for a foul by Zak Ansah in the build-up.
Annoyed with the decision, the home crowd were amused to see referee Jamie Adcock limp off with a calf problem a few minutes later, as fourth official Wayne Barratt took over in the middle.
One of his first actions was to award the winner as Bennett beat two men and produced a lovely pass for Tubbs to finish.
Tubbs had chances to add to his tally after the break, but the missed opportunities did not prove costly.