Tomasz Cywka put the Rams ahead after just three minutes of Saturday's Championship clash before Jonathan Forte equalised with his first goal since the opening month of the season in the 27th minute.
The game's main talking point came 10 minutes later. Alberto Bueno did well to force his way into the penalty area, but once the Spaniard got there he appeared to go down very easily under a challenge from Michael O'Connor.
Scunthorpe complained, but to no avail, and Kris Commons smashed home the spot-kick.
Luke Moore looked to have wrapped up all three points for Derby just before the hour mark but the Iron reduced their arrears to a single goal once more when Gareth Roberts brought down Freddie Sears with 15 minutes remaining.
Roberts received his second yellow card and was subsequently sent off and O'Connor converted the penalty.
However, the Rams held on for a sixth straight win for the first time since they left the Baseball Ground for Pride Park in 1997.
Derby flew out of the blocks and Cywka quickly opened the scoring. Bueno slid the ball inside from the right and the Pole drove a shot into the bottom corner from the edge of the box.
The Rams would have doubled their lead after eight minutes had Joe Murphy not tipped a long-range shot from Commons around a post.
Scunthorpe almost equalised with their first real attack but Rob Jones' header from O'Connor's cross struck a post.
Forte flashed a shot just wide midway through the first half before getting on the scoresheet shortly afterwards.
The striker latched on to O'Connor's pass and shrugged off a Derby defender before beating Frank Fielding from 12 yards.
Murphy was called into action again to deny Cywka but Commons soon put Derby back in front, much to the dismay of all associated with the Iron.
Cywka headed wide at the start of the second half.
The Pole was involved again when the Rams extended their lead, providing the pass for Moore to fire a shot into the top corner from the edge of the area after 59 minutes.
Fielding reacted quickly to keep out O'Connor's free-kick but the on-loan keeper could do little when he faced the Northern Ireland international from the penalty spot.
Scunthorpe could not really take advantage of Roberts' dismissal. Substitutes Trent McClenahan and Garry Thompson had efforts but missed the target, while Josh Wright fired over the bar from long range in a last act of desperation in injury time.