Substitute Kevin Ellison prodded home in stoppage time to earn Newport a 1-0 win over 10-man Port Vale at Rodney Parade and extend their lead at the top of League Two.
It looked like Newport would be frustrated by the visitors, who had captain Leon Legge sent off for a second bookable offence after 69 minutes.
But 41-year-old Ellison's close-range winner in the sixth minute of time added on after a scramble in the box sent Michael Flynn's men three points clear at the top.
An evenly-contested first half saw both sides create plenty of chances.
For Newport, Scott Twine tested visiting goalkeeper Scott Brown with a curling free-kick before Jamie Proctor stabbed wide from close range.
And Liam Shephard had three chances to open the scoring, seeing a fierce drive tipped over and another effort diverted onto the post before flashing a third shot across the face of goal.
At the other end, David Worrall's half volley was well saved by Nick Townsend, as was Tom Conlan's curling effort and Mark Cullen wasted two chances from close range.
Substitute Padraig Amond and defender Brandon Cooper both headed wide late on before Ellison's injury-time winner sealed all three points for the table-toppers.