After a decent start by United to go 2-0 up, they were quickly pegged back and were in danger of losing to 9-man Blackpool until Norwood fired in the equaliser from the edge of the box to make it 3-3 late on.
Paul Heckingbottom made three changes to the side that lost 3-1 at Stoke City. Baldock, Sharp and Osborn all started. McBurnie and Ahmedhodžić returned amongst the substitutes, where they were joined by the fit-again Robinson.
The Blades started like a house on fire, putting the ball in the net inside a couple of minutes before the linesman flag for offside cut the joy short. They didn’t have to wait long before they could celebrate a genuine goal though, on 8 minutes, as Doyle delivered a pinpoint cross to Sharp who cushioned it down to McAtee who netted his first Blades goal.
Ndiaye doubled United’s lead when he nodded the ball home from close-range after Maxwell failed to deal with Norwoods low-driven cross.
On the half-hour mark, the visitors gave themselves hope and Yates held off Osborn to head home at the back post from Dougall’s cross. Then Yates was at it again when he volleyed home his second after some excellent play from Lavery saw him get the better of Norrington-Davies.
United shot themselves in the foot early in the second half, Egan’s touch sent Dougall through on goal and he passed it past Foderingham to put the Tangerines 3-2 up.
Ekpiteta and Baldock were cautioned within a minute of each other before Heckingbottom made a triple change bringing on Brewster, McBurnie and Ahmedhodžić.
Ekpiteta was then dismissed for a late lunge on Brewster after breaking down the left. Thompson quickly followed him off the field for kicking the ball at Ahmedhodžić, leaving Blackpool with just 9 men.
Egan hit the side netting just after those incidents. McBurnie had a header tipped over the bar. Then United was awarded a penalty kick, but Brewster smacked the woodwork.
McBurnie was again denied by Maxwell when he attempted a diving header and Brewster was unable to score the rebound. Ahmedhodzic thought he got the equaliser, but the linesman again flagged for offside.
United was denied a blatant penalty when Connolly handled the ball from a corner that was swung into the near post. Eventually, Norwood fired home the Blades equaliser in the 8th minute of added time, leaving United with no time to get another attack going.
After the final whistle, Foderingham and Lavery were sent off for violent conduct.
Blades: Foderingham, Baldock (Khadra 84), Basham, Sharp (Brewster 64), Egan, Norwood, Doyle, Osborn (Ahmedhodžić 64), McAtee (McBurnie 64), Ndiaye, Norrington-Davies.
Unused: Davies, Robinson, Arblaster.
Blackpool: Maxwell, Connolly, Yates, Dougall, Madine (Hamilton 85), Lavery (Williams 82), Ekpiteta, Thompson, Patino, Thorniley, Bridcutt (Wright 75)
Unused: Carey, Corbeanu, Poveda, Grimshaw.