The teenage striker fired home to secure a 2-1 victory and extend Stanley's unbeaten run to five matches, leaving Wycombe to reflect on a dramatic downturn in form.
The visitors forced the early pace, despite being hampered by the absence of leading scorer Jermaine Easter.
The first chance fell to Scott Golbourne after Kevin Betsy put him through in the third minute, but home goalkeeper Ian Dunbavin parried the ball to safety.
Wycombe appealed for a penalty on 12 minutes when Betsy went down under a challenge from Stanley's Robbie Williams, but referee Mike PIke was having none of it.
Moments later Betsy thought he'd scored when he shot goalwards, but Leam Richardson somehow trapped the ball and it was cleared.
A rare Stanley attack finished with Wanderers goalkeeper Ricardo Batista plucking Michael Welch's header from under the crossbar
The foray forward gave the hosts confidence and after Romuald Boco put a free header over the bar, they took the lead in the 27th minute.
Gary Roberts was fouled on the edge of the area, allowing Ian Craney to smash home the resulting free-kick.
Wycombe appealed for another penalty as Richardson and Betsy tangled on the goalline following Golbourne's cross. The referee again said no and then sent the Chairboys' assistant-manager Steve Brown from the dugout for protesting.
It looked like Stanley would grab a second on 39 minutes when Paul Mullin set up Roberts, but Russell Martin did well to almost take the ball off the foot of the frontman.
Wycombe came out strongly after the break and levelled when Chris Palmer's free-kick could only be touched out by Dunbavin. It fell to Tommy Mooney who headed back into the danger area, allowing Will Antwi to nod home from two yards out.
They should have had a second on the hour when Betsy broke through, but Dunbavin saved.
Welch kept out Mooney at the far post on 73 minutes with a brilliant defensive block, before the veteran hitman skied another effort over the bar.
Wycombe substitute Ikechi Anya should have sewn it up ten minutes from time when Mooney put him through, but ballooned his shot over.
Then, Mullin flicked through for Mangan who evaded a tackle and slotted home the winner.