Carlisle almost pounced to draw first blood after a slow start to the game when O’Hanlon nodded a McGovern free kick back across the face of goal. Berrett tried to cushion it for Miller but Kennedy stepped in to clear the danger and the moment was gone.
Andy Welsh then had more time than he realised for another searching delivery from McGovern. He stole a yard at the back stick but could only guide his tame volley into the side netting as Slocombe scrambled across the cover the angles.
That incident appeared to wake the hosts up and Gillespie had to get down sharply to complete a stunning save from a rasping goal-bound effort from Walker when O’Hanlon lost his balance and stabbed the ball into his path on the edge of the box.
Rory Loy tired his luck with a volley from deep as Carlisle kept plugging away but the Iron’s keeper was well place to grasp it. Matt Robson then found space down the left as he overlapped into the area. His low cross was stopped by Slocombe but he had to recover quickly to prevent Loy from tapping in the rebound.
Scunthorpe rallied and they took the lad following a good period of play as the Iron camped forward in numbers. Duffy showed persistence and his arrowed cross was finished off from close range by the onrushing Akpo Sodje.
Home tails were up and they put their visitors on the rack when Jimmy Ryan bundled Robson out of the way tight by the corner flag. Gillespie and Livesey combined to squeeze the ball behind for a corner but former-Carlisle defender Paul Reid rose highest to convert the set piece and double the lead.
Ton Newey caught everyone by surprise when he ran forward from the half way line just moments later. His crunching shot brought good improvisation from the Carlisle keeper as he stepped back before volleying the wickedly swerving effort away.
The Cumbrians started to show more belief and they had a legitimate penalty appeal waved away as Lee Miller appeared to be pushed in the back by Niall Canavan. Rory Loy then pulled into space and he demonstrated excellent skill as he chested the ball down on the edge of the area, with his back to goal. Reid did just enough to divert the shot on the spin wide.
James Berrett handed his side a lifeline when he picked the ball up from deep. He took Sam Slocombe by surprise with a dipping shot which skipped up wickedly off the surface before finding its way into the bottom corner.
The woodwork prevented Sodje from restoring the two-goal cushion on the stroke of half time as he clipped a Ryan cross past Mark Gillespie. O’Hanlon showed bravery to block a thundering follow-up from the lively Mark Duffy.
Carlisle looked a much better unit after the break and the introduction of teenage superstar Dave Symington gave the Iron defence plenty to think about. A whisked cross just evaded the attentions of Loy and Miller and he brought the best out of Slocombe with one of his now trademark free kicks as he fizzed a powerful effort over the wall.
Jimmy Ryan should have done better at the other end as an attempted clearance crashed into his hands. The ref waved play on but the nippy midfielder rushed his shot and crunched it over the bar when he had time and space on his side.
O’Hanlon had to nod the ball over his own target as Kennedy found another telling delivery and the game became end-to-end as Carlisle started to control the play. A superb cross from Symington fell kindly for Miller but he was unsighted and it ricocheted harmlessly off his shin.
Slick build-up play involving Loy, Miller, Robson and Thirlwell put Berrett into a crossing position as the tempo continued to rise. A block from Reid sat up in front of Symington but he snatched at it and drove his shot onto the roof of the stand.
Sean O’Hanlon tried one from distance as things opened up in front of him but the save of the day was just moments away as the green shirts went in search of their second goal. The agile Iron keeper earned his corn as McGovern provided the magic, Berrett the cross and Beck the sliding volley only for the stopper to spread himself and somehow make the block.
Scunthorpe crept back into it as United committed more and more men forward and Hawley went close with one of his instantly recognisable shots from nothing. Ryan and Duffy then had tame efforts to extend the lead as Carlisle found themselves having to defend.
But the Cumbrian wok rate was made to count for nothing when Akpo Sodje broke through to latch onto a great ball from Ryan deep into time added on. He drew the keeper and finished things off with a crisp finish into the bottom corner.
Scunthorpe - Sodje (17, 90), Reid (22)
United - Berrett (45)
Scunthorpe - Walker (65), Newey (85), Kennedy (86)
United - O'Hanlon (11), Thirlwell (67), Berrett (69), Simek (81)
Scunthorpe United - Slocombe, Newey, Reid, Canavan, Kennedy, Duffy (Mirfin 78), Collins, Walker, Ryan, Hawley, Sodje. Subs - Severn, Barcham, Grella, Godden, Nolan, Adelakun.
Carlisle United - Gillespie, Simek, Livesey (Cadamarteri 90), O'Hanlon, Robson, McGovern, Berrett, Thirlwell, Welsh (Symington 46), Miller, Loy (Beck 72). Subs - Collin, Murphy, Noble, Potts.
Referee - Mr David Coote
Attendance - 3,112 (200 away fans)