The Valiants came from behind to defeat the Stags thanks to James Wilson and an off the bench brace from Kian Harratt to make it three home wins on the spin.
Nigel Clough’s side arrived in Burslem with just one defeat in 14 league games in their own bid for promotion to League One.
It was the Valiants who started the game on the front foot, both Chris Hussey and Connor Hall played dangerous crosses into the box which forced the Mansfield backline into important clearances.
However, the visitors opened the scoring against the run of play midway through the first half when Rhys Oates beat Aaron Martin to a long ball, before he rounded Aidan Stone and slotted into an empty net.
Vale nearly responded in the perfect manner minutes later; Tom Pett volleyed a shot into the ground, but it drifted just wide of the post.
In the 33rd minute the Valiants got their equaliser. Ben Garrity threaded a ball through for James Wilson, who rode a sliding challenge and drilled a low strike between the hands of Nathan Bishop.
Vale began the second half in similar fashion to the first; Hussey delivered a deep cross for Wilson to nod back, and Harry Charsley fired towards goal which was well blocked.
There was then a penalty shout in the 52nd minute as Garrity flicked a header onto Jamie Proctor, who was one-on-one with Bishop and appeared to be pulled back before getting to the ball. Moments later, Hussey swung a corner in for Garrity to rise highest and head over the bar.
The Stags created their first chances of the second half on the hour mark, with Stone making an important double save; first from Jamie Murphy, followed by George Lapslie from close range.
Andy Crosby introduced Harratt as a substitute in the 72nd minute and four minutes later he put Vale in front. A flicked header found him on the wrong side of the Mansfield defence, he saw his first effort saved but reacted quickest to convert the rebound.
Mansfield could have drawn level four minutes from time when Nathan Smith deflected Lapslie’s cross onto the bar.
Harratt netted his second of the night just a minute later; Mal Benning delivered a wide free kick to the back post and Proctor kept the ball alive for Harratt to finish from the middle of the area.
The Valiants then comfortably saw out the remaining few minutes of the match as they secured a much needed three points under the Vale Park lights.
Port Vale | Stone, Hall, Smith, Worrall, Garrity, Wilson (73’ Harratt), Proctor, Hussey (67’ Benning), Martin, Charsley (70’ Walker), Pett.
Subs not used | Holy, Amoo, Edmondson, Cooper.
Mansfield Town | Bishop, McLaughlin (86’ Bowery), Rawson, Murphy, Clarke (56’ O’Toole), Hawkins, Perch, Oates (79’ Johnson), Wallace, Stirk, Lapslie.
Subs not used | Hewitt, Maris, Stech, Law.