Paul Heckingbottom claimed a bad offside call cost Sheffield United a vital win at Blackpool after a late Oliver Norwood goal was ruled out in the 0-0 draw.

Norwood thought he had won a tight game for the Blades deep in the second half with a deflected shot from inside the box, only to see the linesman wave the flag.

With United unable to find a winner, the decision proved costly and the draw means the promotion-chasers have now won just one of five games and dropped to ninth in the table.

“It was a mystery decision in my eyes,” Heckingbottom said.

“We knew it would be a tough ask here and it could turn into a war of attrition, but I’ve seen the late one back and the linesman has apparently seen one or maybe two of our players in the way of the shot.

“There are times when a linesman just shouldn’t get involved in big decisions, and this was another instance tonight.”

United bossed the first half at Bloomfield Road but struggled to break down a tough Blackpool defence and they found themselves on the back foot for much of the second half.

“It just goes to highlight again, though, that you have to work hard and earn every single point in this division – you have to earn everything,” Heckingbottom added.

“We deserved to get the three points and we earned the three points, but tonight we didn’t get them and that’s a big disappointment.

“Maybe the quality you need just wasn’t there at the top end, but that’s something we go away and work on.”

The draw ends Blackpool’s run of three straight league wins but manager Neil Critchley was again pleased with his team’s performance.

Josh Bowler almost scored in the first half when his shot crashed off the bar, while CJ Hamilton wasted a fine chance to win it by blazing over from 12 yards.

“I thought it was a really entertaining 0-0 draw,” he said.

“I thought Sheffield probably edged it in the first half and maybe we were lacking that bit of self-belief. Throughout the second half, though, we were in the ascendancy, and if any team was going to go on and win it, it was us.

“We’re disappointed with a point against a side like Sheffield United, but that just goes to show how far we’ve come in recent seasons.

“I was really energised myself with our second-half performance – I could see us growing into the game with each passing minute.

“I then rolled the dice in the last 15 minutes and changed the formation, but it didn’t quite come off.

“We definitely tried our best to win it, and we nearly did I thought, but it just wasn’t to be. We gave it our best shot, but we just fell a little bit short.”