Richie Barker’s hopes for a winning start to his Pompey managerial career were left in tatters as Newport claimed a 2-0 win at Fratton Park.
Two goals in the space of three second-half minutes from Michael Flynn settled the game as the Welsh club picked up a second win over Pompey this season, following their Johnstone’s Paint Trophy romp last month.
In an even first half, Pompey had the best chance of the opening 45 minutes as Patrick Agyemang saw an effort somehow cleared off the line.
But Newport looked dangerous and had their moments themselves, although they failed to create a serious clear-cut opening.
The visitors took command after the break, though, as Flynn broke the deadlock, rifling high into the net.
And they doubled their advantage soon afterwards when Flynn drilled home at the far post for his second of the day.
Pompey had little response, although substitute Jed Wallace struck a post with a sliding effort.
It was precious little for a crowd of more than 15,000 once again, and Barker will surely now know he has a sizeable challenge on his hands to turn around a season that is sinking fast.