Mansfield dropped out of the League Two play-off places despite winning 2-1 at Newport.
The hosts started brightly and captain Mickey Demetriou headed onto the bar early on.
But they fell behind in the 24th minute when Hiram Boateng got the better of Cameron Norman after a throw-in was flicked on into the six-yard box and he fired past Joe Day from close range.
Will Evans, who impressed at left wing-back for Newport, so nearly levelled on the hour but he was denied by a superb save from Christy Pym.
Substitute James Gale, who also hit the post late on, doubled the Stags’ advantage when he capped off a swift counter-attack with a fine finish after 73 minutes.
Boateng turned provider this time as he picked up the ball on the edge of the Stags box and released Gale, who showed great composure to find the bottom corner.
Exiles subs Aaron Lewis and Aaron Wildig combined after 86 minutes and the latter’s far-post header was enough to drop Mansfield below Salford in the table on goal difference.
