Despite Tyler Walker's 83rd-minute equaliser, Mansfield's afternoon ended in defeat following Ilias Chair's last-gasp winner.
It was a frantic encounter that began to open up when Kurtis Guthrie broke the deadlock midway through the second period.
Walker’s smart finish restored parity for all of nine minutes before Chair secured three points for the away side in the 92nd minute.
David Flitcroft named one solitary change for Saturday’s outing as Will Tomlinson replaced Jorge Grant.
Amidst blustery conditions at One Call Stadium the Stags began to hunt down the all-important opening goal.
Mal Benning, with only Mansfield’s second free-kick of the encounter, forced Paul Farman into a smart near-post stop.
This unfolded just minutes before Will Tomlinson was also denied, following a crisp passage of play.
The hosts showed little signs of easing but had to keep their concentration when Stevenage began to ease into the game.
Conrad Logan made a huge, close-range save to thwart Michael Timlin before Guthrie clipped the post with his header from a corner.
The Stags ‘keeper then produced a moment of brilliance to prevent Chair’s effort from distance nestling into the top corner.
Mansfield had weathered the storm that Stevenage had conjured and looked to profit from a mistake at the back, soon after.
Ben Nugent hacked CJ Hamilton as the winger was inches from racing clear – with Benning unable to direct his subsequent effort through the crowd of bodies that faced him.
An even first period concluded without a mark on the scoresheet from either side.
But with only three minutes elapsed in the second half, the Stags almost did just that.
Benning pumped a delivery into the middle and it looked to be sneaking under Farman’s crossbar before the shot-stopped quickly turned it behind.
The home side continued to ramp up the pressure – and the Stags faithful responded in fine voice.
Gethin Jones applied pressure at the back post as he sought his first goal in Mansfield colours, yet it was defended smartly by Nugent.
Walker then latched onto a bouncing ball but was unable to find the desired connection as it ran wide of Farman’s upright.
However, for all of Mansfield’s endeavour, they were dealt a killer blow in the 71st minute.
Guthrie found himself with just enough space inside the Stags’ area to be able to bring the ball under his spell and fire a spectacular volley beyond Logan.
The Stags would not lie though.
Mellis stung the palms of Farman from distance and the follow-up saw Hamilton’s goal-bound effort blocked superbly by Nugent.
Substitute Danny Rose then had a brilliant chance to draw his side level but nodded over the bar.
And on 83 minutes, for all their hard work, Mansfield had their reward.
Logan claimed possession and wasted no time in finding Walker down the other end of the field with an exquisite ball.
The on-loan striker subsequently spotted Farman off his line and proceeded to poke the ball beyond the stranded ‘keeper.
With a final roll of the dice – with the clock ticking into additional time – Benning made way for Alex MacDonald.
But it was Stevenage who instead found the vital third goal in the encounter.
Chair made his way forward and when possession eventually fell to the midfielder he was able to find the back of the net from the edge of the area.
The result leaves Mansfield in third place in Sky Bet League Two with an all-or-nothing fixture rounding off their campaign away to MK Dons next Saturday.
STAGS XI: Logan (GK), Benning (MacDonald 90’), Preston, Pearce ©, Bishop, Mellis, Tomlinson (Rose 64’), Sweeney, Walker, Jones (Grant 73’), Hamilton.
SUBS NOT USED: Smith (GK), Atkinson, Turner, Hakeem.
STEVENAGE XI: Farman (GK), Wildin, Timlin, Cuthbert ©, Byrom, Sonupe (McKee 81’), Chair, Vancooten, Guthrie, Nugent, Martin.
SUBS NOT USED: Byrne (GK), Hunt, Revell, Gibson, Smyth, Wilkinson.
REFEREE: Darren Drysdale.
ASSISTANTS: Ravel Cheosiaua & Peter Gooch.
FOURTH OFFICIAL: Alan Clayton.
ATTENDANCE: 6,390 (209 away).
