The Iron had to settle for a point after nine men Sheffield United scored a late equaliser through defender Neill Collins.
United's newest recruit Leon Clarke scored within five minutes after coming on as a substitute when he towered above Sheffield United defender Harry Maguire to head the ball into the bottom corner of Mark Howard’s goal after Mark Duffy played a lovely weighted chip into the box.
The former Sheffield Wednesday striker could have scored his second of the game with minutes to go after Duffy’s ball into the box was cleared just before he could strike the ball into the net.
Danny Wilson’s side drew level on 82 minutes when Neill Collins headed past Sam Slocombe from 12 yards after Tony McMahon delivered an inch perfect ball.
Referee Steve Rushton sent Sheffield United captain Michael Doyle off inside the first 15 minutes, after he kicked Iron striker Mike Grella in the back after the American held off the opposition midfielder.
Rushton then showed his fifth red card of the season when he dismissed Ryan Flynn on 72 minutes after a reckless challenge on Iron right-back Christian Ribeiro, which left the Iron defender requiring lengthy treatment.
In a first half stalemate, Iron striker Mike Grella had the best chance to put the home side in the lead, just before the break when he tried an audacious effort from 25 yards, however it sailed clear over Howard’s goal.
Despite being down to 10 men, Sheffield United could have taken the lead on half an hour when Nick Blackman shot from the edge of the Iron box, but Iron captain David Mirfin blocked the shot well.
Mark Duffy weaved inside and out of the Blades’ defence on 37 minutes to create another goal scoring opportunity, however stand-in captain for the visitors Collins cleared from the crowded box.
Former Leeds United striker Grella caused chaos in the visitors' defence before laying the ball back to Walker, who returned to the side following a one-match suspension, failed to connect properly with his shot.
The Iron started the second half the brighter, with two successive corners.
The first of which was met by Mirfin who headed the ball on to Harry Maguire, who turned the ball behind.
On 50 minutes, Grella played in Walker again who was unlucky as his effort was blocked by the defender and then ricocheted back off the Iron number four.
Scunthorpe's new signings Leon Clarke and Karl Hawley were both introduced to Glanford Park action on 55 minutes when they replaced Grella and Connor Jennings.
The Blades could have dran level just after the hour mark, when Collins climbed above the Iron defence before his header crashed against the crossbar.
The Iron had the chance to retake the lead minutes after being pegged back when Josh Walker’s chip had Howard scrambling backwards before he got the slighted touch to send the ball behind for a corner.
As the fourth official put the board up for five minutes added time, Iron substitute Jimmy Ryan won the home side a corner. However, they were unable to capitalise after Mirfin misjudged the flight of the ball.
Injury time left the United defence nervous after they conceded a late free-kick in a similar position to the one which they conceded from. However, the visitors were happy to settle for the draw as the played the ball towards the right corner flag.
Scunthorpe United: Slocombe, Ribeiro, Mirfin, Canavan, Newey, Walker, Prutton, Duffy, Barcham (Ryan, 90), Grella (Clarke, 55), Jennings (Hawley, 55).
Substitutes not used: Severn, Hughes, Keegan, Gibbons.
Sheffield United: Howard, McMahon, Maguire, Collins, Hill (Williams, 69), McAllister (Cresswell, 70), Doyle, McDonald, Flynn, Cofie (Miller, 82), Blackman.
Substitutes not used: Westlake, Harriott, Ironside, Long.
Attendance: 5,533 (2,322 away).