Mansfield’s Andy Cook and Mal Benning returned to haunt their former club as they helped inflict a fifth successive defeat on Walsall.
Cook headed the Stags ahead and Benning set up Alex MacDonald’s winner after Elijah Adebayo levelled for the Saddlers.
Both sides threatened early, Nicky Maynard’s glancing header well saved by Walsall goalkeeper Jack Rose before Stags stopper Conrad Logan’s legs denied Saddlers striker Rory Gaffney.
Mansfield led on 30 minutes as Otis Khan’s deep cross was headed home by summer signing Cook – Walsall’s top scorer last season – from close range.
Walsall could have equalised immediately as Adebayo robbed Krystian Pearce and backheeled to Gaffney but his goalbound shot was blocked by Benning.
The hosts did level on 45 minutes as Adebayo buried a close-range header from Rory Holden’s free-kick.
They should have led midway through the second period but Gaffney was again denied one-on-one by Logan.
And Walsall, who drop to 21st, were made to pay as Benning charged into the area to feed MacDonald to rifle home the 68th-minute winner from six yards.