Bury stunned Scunthorpe with a fine second-half comeback in an impressive victory at Glanford Park.
Shane Duffy gave the Iron an early lead, touching in Michael O'Connor's free-kick, while team-mate Andy Barcham was denied by Cameron Belford.
But Peter Sweeney fired the leveller from 20 yards and Bury took control.
Andy Bishop put the Shakers 2-1 ahead after good work by Mike Jones and Efe Sodje's header added a third to leave Scunthorpe in the drop zone.
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Scunthorpe manager Alan Knill told BBC Radio Humberside:
"I thought we were excellent first half and pretty poor second half but poor decisions have cost us.
"That's football isn't it. You can see goals but it's what you do about it and the second goal was the one that killed us.
"We stepped forward first half and played in their half but in the second half we stepped backwards. We've never told anybody to step backwards but that's what we tend to do."
Bury manager Richie Barker told BBC Radio Manchester:
"We were extremely fortunate to only get to half-time at 1-0 down, but then in the second-half I thought we were fantastic.
"We had a couple of scares to be fair but I thought as the game went on we just became the better side.
"He (Alan Knill) signed most of the players that were here when I got here, so I think it was a little bit strange as for one or two of them it may be the first time they've played against an ex-manager.