Two-goal Michael Spellman and Cameron Evans were the County heroes as Christian Fuchs' battlers finally blasted out of the league drop zone after an agonising 208-day entrapment.
This was Newport's biggest home win of the season and the margin of victory might have been even greater, such was the creativity of the Port – with goal-scorer Evans, Sven Sprangler, Ryan Delaney and Courtney Baker-Richardson all thwarted in their efforts to pile on the misery for free-falling Tranmere.
Rovers lost their skipper Sam Finley to a red card in first-half added time for a crunching challenge on Austrian Sprangler – and that opened the door for the Exiles to stretch their opponents to the maximum, particularly after the hour mark.
Spellman cancelled out Finley's early opener on the half-hour and then bagged a third deep into stoppage time, Evans scoring the critical winner in the 89th minute.
Rising County have gathered seven points from their last four games and this latest triumph means destiny is now firmly back in their own hands – with leapfrogged fellow strugglers Harrogate and Barrow among the Exiles' final 11-match run-in, as well as Crawley. Next up, though, is Colchester at NP19 this Saturday.
The Port made a couple of tweaks to the line-up that secured a vital goalless draw at Fleetwood three days earlier – former Cardiff City left-back Tom Davies returning, with Cameroonian pace-man Bobby Kamwa partnering Baker-Richardson at the cutting edge. But it was a never-say-die attitude that proved the crucial ingredient as Rodney Parade rocked.
Andy Crosby's 19th-placed Rovers needed to halt a disastrous run that had seen them crash seven times in their last nine games – taking just six points from a possible 27. The team from Birkenhead switched to a flat back four, Cameron Norman coming in at right-back and Patrick Brough moving to left-back. Omari Patrick slotted into the left of a midfield four, with Kenyan Zech Obiero tucked in behind sole striker Joe Ironside.
The new formula worked to devastating effect as the visitors snatched a lead after just 102 seconds. Newport paid a huge price for only half-clearing Patrick's in-swinging corner, linkman Finley despatching an 18-yard right-foot half-volley past a rooted Jordan Wright.
Nerves were jangling, the midfield exchanges a morass littered with misplaced passes from both rivals. County looked to creep forward when opportunities arose. Kamwa cut inside Norman, Tranmere's Stephan Negru hacking clear the danger.
County chief Fuchs had clearly opted for a high-press strategy. A concentrated period of urgency from the Port saw Rovers dramatically wilt in the 36th minute. An unselfish Baker-Richardson teed up Spellman on the edge of the box, the Geordie flashing a low left-foot strike past Marko Marosi via the post.
It was the ex-Sunderland man's fourth goal of the campaign and, despite Wright comfortably pouching snapshots from James Plant and Obiero, this increasingly feisty clash swung County's way in the third minute of first-half added time.
Baker-Richardson, relentlessly buffeted by his Rovers markers, was cautioned for dissent and Kamwa for challenging Marosi late. In between those incidents, after pole-axing Sprangler with a crude lunge, Tranmere's Finley – already booked – rightfully attracted a straight red card from referee Isaac Searle.
Newport sought to stretch Tranmere's ten men at every opportunity, but the hosts still needed to be vigilant against sharp Rovers counters. Substitute Nohan Kenneh and Plant linked smoothly on the right and Evans was required to block Obiero deep inside the area.
Yet the Port were upping the ante around the hour mark as the black and amber shirts poured forward in search of another breakthrough. Evans lifted a drive over the bar, Sprangler also went close, before Spellman extended Marosi with a dipping effort.
County forced six corners as the clock ticked past 75 minutes. Tough-tackling Sprangler curled an effort fractionally wide of the crossbar and Rovers centre-back Nathan Smith had to react sharply to frustrate a diving Baker-Richardson at the near post.
County's frustration must have escalated as battered Rovers grimly held on. Delaney was spectacularly thwarted by Marosi after a Davies free-kick sparked bedlam, substitute Nathan Opoku then threatening.
Yet Rovers finally crumbled in the 89th minute. Kamwa's magical feet wove space on the left and Evans sprang low, bravely pouncing to bag the critical winner County thoroughly deserved.
Stunned Tranmere advanced frantically, searching for a route back into a contest that slipped definitively from their grasp six minutes into additional time. The Port turned defence into a razor-sharp attack, Opoku cleverly feeding Spellman, who coolly slotted into an empty net from 30 yards with an advanced Marosi hopelessly out of position.
