Nigel Pearson's men started brightly and striker Matt Fryatt was twice denied in the early stages by Iron goalkeeper Joe Murphy.
The visitors did go in front after 22 minutes when Lloyd Dyer raced through unchallenged for a well-taken goal.
The strike stirred Scunthorpe into action and Paul Hayes saw one shot deflected just wide and another well blocked by goalkeeper Paul Henderson.
Hayes then equalised after 32 minutes with a fierce shot from a tight angle which flew home off the inside of the far post.
There were few chances at either end in the second half until midfielder Andy King raced through a square home defence to slot into the bottom corner from the edge of the box.