At the hour mark the Derbyshire side held a two-goal lead, they only had two shots and one of those was a penalty.
Scunthorpe then got a break and for the final half hour they took control and fully deserved to get something from the game.
Loan man Neil MacKenzie was the star man for the Iron, he literally worked his socks off to inspire his team-mates, with Ian Baraclough also playing a starring role.
Steve Blatherwick was the key man for the Spireites, his powerful display at the centre of defence saw him give little scope to the home side.
Chesterfield made an early break, scoring after only four minutes, this followed a throw by Kevan Hurst which was flicked on by Blatherwick and Paul Hall claimed his 10th of the season with a header at Tommy Evans' right-hand post.
The visitors were strong in defending the lead although Baraclough forced a brilliant save from Barry Roche.
Scunthorpe were sadly lacking in ideas, MacKenzie inspiring most of their good moves although Roche did well to block Billy Sharp's effort and Andy Keogh had the ball in the net from close range but he was deemed offside.
MacKenzie failed to take a golden chance in the opening minutes of the second half, he was on the goal-line when he was dispossessed.
Chesterfield then consolidated their lead from the spot when Shane Nicholson sent Evans the wrong way, this followed a foul in the box by Iron skipper Andy Crosby on Derek Niven.
Seven minutes later Scunthorpe were back in the hunt when Baraclough drove home a superb shot from 30 yards. That gave the Iron a lift and Roche did well to save from MacKenzie and Richard Hinds blasted over the top.
Scunthorpe's last throw of the dice saw Tommy Johnson introduced with ten minutes left.
With 60 seconds remaining on the clock when he was on the spot to knock the ball home after Roche had blocked a MacKenzie shot.