Mansfield dropped out of the Sky Bet 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.
And substitute James Gale, who also hit a post late on, doubled the Stags’ advantage when he capped off a swift counter-attack with a fine finish in the 73rd minute.
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 subtitutes Aaron Lewis and Aaron Wildig combined in the 86th minute and the latter’s far-post header was enough to drop Mansfield below Salford in the table thanks to goal difference.
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