Laws: I'm bitter, angry and disappointed
United were two goals down inside the opening 10 minutes, eventually losing 5-2 - with Peter Beagrie and Neil MacKenzie scoring.
Laws said: "I'm bitter, angry and disappointed. What I have said to the players in the dressing room will stay in there.
"I put the team out and it's their job to go out and perform, but I'm made to take the blame and I'll take that.
"You cannot give a team like Barnsley a two goal start.
"Right from the first 10 minutes we were spineless and it was effectively game over.
"We cannot take any plusses from the performance. Every game that goes by it becomes even tougher and harder for us to turn it around."
Tykes boss Andy Ritchie singled out former Iron striker Paul Hayes, who scored and set up another, for praise.
He said: "The goal capped off an excellent day for Paul.
"He was very up for the game, he took quite a bit of stick at the warm-up and that's the best way to reply. And we're very pleased that he stuck his
chance away at the end.
"We put them under pressure early doors, we were all over them like a rash and it paid dividends.
"Once we got the upper hand some of the movement and chances were top-notch. We know that we have got goal-scorers in the side it's just making sure that when we get the chances we are more clinical."