Newport's survival hopes suffered a setback as they threw away an early lead and had Jaanai Gordon sent off in a 2-1 defeat at Mansfield.
Gordon was dismissed midway through the second half for a second foul in as many minutes and the 10 men were punished in the 75th minute when Craig Reid handled a Shaq Coulthirst shot.
The Peterborough loanee tucked away the penalty - his third spot-kick for the Stags - to secure victory for the Stags.
Newport went ahead after just five minutes when Ryan Bird swept a loose ball home from close range after keeper Jake Kean had managed to block Gordon's close-range shot from a low left-wing cross by Dan Butler.
Mansfield were level after 17 minutes as Krystian Pearce controlled a Joel Byrom free-kick into the box and prodded home under the keeper.
Paddy Hoban should have put Stags in front five minutes later when put through by Coulthirst but Joe Day smothered his first attempt and then Mickey Demetriou cleared his follow-up off the line.
Mansfield lost keeper Kean in the 39th minute after he was hurt in a collision and was replaced by Scott Shearer.
A poor second half livened up after Gordon's dismissal and the Stags finally put the game to bed with the penalty.