Iron manager Nigel Adkins felt his team could have got a result at Blackpool on Saturday, but said the sending off of Joe Murphy was the turning point for his side as they went down 4-1.
Following an even first half when United looked comfortable, the game exploded into life at the start of the second period when Paul Hayes clipped Scunthorpe ahead.
Ian Evatt soon equalised with a towering header though, and at around the hour mark Murphy was sent off for saving a shot outside his penalty area after the hosts had broken through on the counter-attack.
Sam Slocombe replaced Murphy and his first job was to pick the ball from the back of the net after Charlie Adam lashed home a free-kick.
Former Hull man Ben Burgess added a third soon after to kill off any hopes of a point for United.
Then, in the dying stages, Alex Baptiste drilled in a shot from the edge of the area, to add a final gloss to the scoreline.
"I felt that initially we showed good resolve and had a great shape about ourselves, which we'd worked on," said Adkins, speaking on The Iron Player.
"We were solid defensively and a very good Blackpool side found it tough to break us down.
"We knew, coupled with that, if we could get hold of the ball we would create chances for ourselves.
"We defended very well in the first half, and had two great chances through Paul Hayes and Matt Sparrow before the break.
"On another day we'd have given ourselves the lead through those good passages of play.
"At the start of the second half Paul Hayes managed to score exactly what we were working on, and he could have had a couple before as well.
"We had good chances to put ourselves in the lead. We worked very hard and were rewarded.
"But, again, goals change games and we were disappointed with the free kick that we gave away for Evatt's goal. It was disappointing that one person just knocked off a little bit which allowed a quick free kick to be taken into the penalty area.
"For an hour we were great but in a crazy five minutes the game was lost.
"Joe Murphy did great to go out and win the first challenge with a good tackle, and then made a reactionary save outside the box, got sent off and that changed the whole complexion of the game.
"They were back in it, and Charlie Adam scored a fantastic free-kick.
"For the third goal, it appears Sam Slocombe got two hands on the ball and the player actually went and stamped on his elbow to take the ball out his hands. Until I see it on the video I can't really comment further. Sam's got a nasty cut on his elbow though.
"We had a mountain to climb then against an exceptionally good football side in a rich vein of form, who played some excellent football."
Hear much more from Nigel Adkins, Andrew Wright, Joe Murphy and Ian Holloway on The Iron Player.
