Keeper Jamie Young was to blame, allowing D'Laryea's fierce 20-yard drive to spin from his grasp and into the top corner - ironically moments after he had saved superbly to deny substitute Danny Reet a late goal.
Just two minutes earlier Wycombe thought they had clinched their fourth win in five games when home keeper Jason White spectacularly beat away two powerful close range strikes from Tommy Mooney and substitute Jermaine Easter.
It was Mansfield's first win in five outings and followed a thrilling first half of four goals in 16 minutes - including two goals inside 60 seconds.
Stags striker Micky Boulding was a victim of a virus running through Field Mill, allowing Scottish U19 international Bryan Hodge to make his debut on loan from Blackburn Rovers.
And the teenager almost made an immediate impact when his third minute deflected cross was almost headed in by Simon Brown, the wingman's back flick clutched under the bar by keeper Jamie Young.
Wycombe hit back immediately and might have grabbed two early goals. First Lionel Ainsworth weaved his way into the area and saw his fierce low drive kicked away by Jason White, before the keeper then dived full length to clutch Tommy Mooney's spectacular shot.
In a fast and furious opening, the young keeper also did well to block Scott McGleish's poked close-range effort as Wanderers impressed with quick passing and clever running off the ball.
Those saves proved vital in the 21st minute when full-back Johnny Mullins rose highest to powerfully head in Brown's right-wing corner, with keeper Young only able to parry the ball into the bottom corner.
But within six minutes Wycombe were deservedly level. Anthony Grant winning the ball from Jonathon D'Laryea and McGleish crashing a terrific 25-yard shot into the bottom corner.
In a remarkable first half, the Stags regained the lead in the 36th minute only to lose it 60 seconds later.
First Stephen Dawson and Gareth Jelleyman combined down the left before the full-back's astute pull back was swept in by Martin Gritton - his sixth goal in nine games at Field Mill.
But straight from the kick-off Mooney muscled Mullins off the ball as the Mansfield defender failed to clear and McGleish glanced in Mooney's quick cross for his third goal in two games.
As the goalmouth action continued to come thick and fast, Jake Buxton's incisive pass found Gritton and his first-time shot was just deflected wide by the heels of keeper Young. With Mansfield now on top, Brown's injury-time chip landed on the roof of the net.
The second half started equally wide open with chances at both ends, but the Stags created the clearer opportunities.
Hodge's low cross was cut out by the keeper with Wycombe's defence stretched, Brown had a strong penalty appeal turned down, and Young charged out of his area to deny D'Laryea.
Young then saved superbly to deny Mullins a second goal after yet another fine pass from Hodge, who starred on his debut, had opened up the Wanderers' defence.
The increasingly effective Brown flashed a low-half volley past the diving keeper and narrowly wide.
Wycombe finished the game the stronger and it needed two fine reflex saves from White to keep the Stags level. First he beat away Mooney's close-range finish and then parried substitute Easter's stinging blockbuster.
Then came D'Laryea's late winner.