Wycombe goalkeeper Jamie Young made a late mistake to allow Jonathan D'Laryea to score a dramatic late winner. Johnny Mullins put Mansfield in the lead with a header from a Simon Brown corner before Scott McLeish equalised with a strike from 25 yards.
Martin Gritton converted Gareth Jellyman's pass to restore the Stags' lead before McGleish levelled again, heading home a Tommy Mooney cross.
But D'Laryea's 20-yard strike squirmed past Young for the Mansfield winner.
Mansfield: White, Jelleyman, Baptiste, Buxton, Mullins, Hodge, Dawson, D'Laryea, Brown, Gritton (Reet 84), Conlon (Arnold 68).
Subs Not Used: Muggleton, Hjelde, Charlton.
Booked: Dawson, Reet.
Goals: Mullins 21, Gritton 36, D'Laryea 87.
Wycombe: Young, Golbourne, Crooks, Williamson (Christon 87), Martin, Palmer, Grant (Torres 65), Bloomfield, Ainsworth, Mooney, McGleish (Easter 75).
Subs Not Used: Gregory, Onibuje.
Goals: McGleish 27, 37.
Att: 2,711
Ref: A Penn (W Midlands).