Substitute Kevin Ellison prodded in a winner six minutes into stoppage time to earn Newport a 1-0 victory over 10-man Port Vale at Rodney Parade and extend their lead at the top of Sky Bet League Two.
It looked like Newport would be frustrated by the visitors, who had captain Leon Legge sent off for a second bookable offence on 68 minutes.
But 41-year-old Ellison's close-range winner after a scramble in the box sent Michael Flynn's men three points clear at the top.
The win gave them breathing space over second-placed Cheltenham, who kept up their chase with a 3-0 win against Walsall.
Dan Scarr's own goal and Matty Blair's strike early in the second half set the hosts on the path to victory, before Ben Tozer completed the scoring in the 88th minute, touching a Chris Hussey free-kick past Saddlers goalkeeper Liam Roberts.
Carlisle are two points behind Cheltenham after they triumphed 3-0 at Crawley, subjecting the hosts to their first defeat at home in 15 league matches.
Rhys Bennett opened the scoring before Joshua Kayode and Aaron Hayden found the net in the second half, with David Sesay sent off late on for a foul on Omari Patrick.
Exeter lost ground on their promotion rivals as their 13-match unbeaten run in all competitions was ended in a 2-1 defeat to Oldham.
Randell Williams put the home side in front after 12 minutes but George Blackwood levelled with a fantastic curling effort nine minutes later and Danny Rowe clinched the three points with an unstoppable free-kick.
Nicky Cadden's last-gasp free-kick stole a point for Forest Green in an entertaining 2-2 draw at Barrow.
Elliott Whitehouse gave the visitors the lead in the 52nd minute, but Luke James' goal and a Dior Angus penalty looked to have snatched the win before Cadden stepped up deep into stoppage time.
Two first-half goals provided enough of a cushion for Bolton to see off a struggling Stevenage side with a 2-1 win at the Lamex Stadium.
Eoin Doyle and Ali Crawford netted in the opening 36 minutes, while Tom Pett's 44th-minute strike was as much of a response as Stevenage could muster.
James Vaughan scored a first-half double as Tranmere made it three league wins on the bounce and put Grimsby to the sword in a 5-0 victory at Prenton Park.
Vaughan's double and goals from Peter Clarke and Otis Khan had Rovers 4-0 up in 34 minutes, before Paul Lewis completed the rout late on.
Aaron Wildig netted a stoppage-time equaliser as Morecambe snatched a 1-1 draw at improving Scunthorpe, who had taken the lead 10 minutes from time through Manny Onariase.
First-half goals from Luke Burgess (2) and Ian Henderson saw Salford to a 3-0 win at home to Bradford while Leyton Orient beat Harrogate by the same scoreline courtesy of Danny Johnson's hat-trick.