Report: Wycombe 0-1 Stags
Stags' defender Krystian Pearce applied the finish from short range after heading against a post from Joel Byrom's excellent free-kick in the 14th minute.
And Mansfield's lead could have been further extended in a dominant first half, with the otherwise impressive Alfie Potter missing a hat-trick of chances in quick succession.
The victory breathes new life into the club's play-off ambitions in what is likely to be a highly exciting finale with four games remaining in Sky Bet League Two.
Defender Hayden White returned to the line-up after a hamstring strain, while midfielder Alfie Potter was also handed a starting berth.
After 90 seconds, striker Danny Rose tested the handling of Wycombe goalkeeper Jamal Blackman with a dipping strike from 20 yards - but the home shot-stopper was equal to it.
Rose then flicked it on to Potter in the 11th minute, and his pass found Matt Green who struck low against Blackman, yet the flag was up for offside.
As the game crept into the 14th minute, Stags took a deserved lead for their positive early play. Rhys Bennett showed excellent skill to keep the ball in play on the right touchline, sidestepping his man to knock the ball up field. And after neat play between Ben Whiteman and Danny Rose, the striker was brought down 35 yards from the Wycombe goal.
Joel Byrom delivered the set-piece with pin point accuracy onto the head of a towering Krystian Pearce inside the area. And after his effort came back off a post, the centre-half was quickest to react to stroke the ball home from close range.
Wycombe swung a flurry of crosses into the Mansfield box but a combination of good punching from Jake Kean and imposing aerial defending, prevented a Wycombe leveller.
Rose and Whiteman again combined before the latter slipped it to Potter inside the area. But the midfielder's eventual shot was blocked and turned behind for a corner.
In the final minute of normal time, powerful Wycombe marksman Ade Akinfenwa appeared to push Krystian Pearce, 22 yards out, before sending a venomously-hit volley onto the roof of the net.
Nine minutes into the second half, Akinfenwa connected in the air from Garry Thompson's right-channel assist, yet Bennett was well-placed to deflect it behind for a corner.
The giant frontman turned on the edge of the area to sky a shot well off target in the 59th minute.
Thompson came much closer a minute later, cutting in from the right to fire beyond the angle.
Five minutes later, Alex MacDonald entered the field for Alfie Potter in Stags' second change.
On 72, Wycombe hitman Scott Kashket unleashed a ferocious shot from the edge of the area, but a brave George Taft flung himself in front of the attempt and the ball spinned behind for a corner.
Kean had to get down low to beat away a left-footed free-kick by Joe Jacobson from 25 yards, which snuck over the wall.
Kean was on top again in the 89th minute when Akinfenwa nodded goalwards from a route one ball - but Kean expertly palmed it behind at full stretch.
Then in the dying moments, Stags somehow managed to thwart a Wanderers attack, amidst a crowded box, after a cross from the right flank.
And after a professional display rich in endeavour, Stags claimed the points to set up a hotly contested battle on Easter Monday at One Call Stadium with play-off rivals Luton Town.
UNUSED SUBS: Jensen, Howkins, McGuire, Baxendale
ATTENDANCE: 4,218 (305 Stags' fans)