Craig Elliott said he felt ‘proud’ of his Pilgrims despite their 3-1 defeat to table-topping Stockport County.
Darren Stephenson, Elliott Osborne and Frank Mulhern won it for the Hatters, despite United being given hope by Ben Davies’s penalty.
But Elliott was left questioning some key decisions by referee Amy Fearne, including one which went United’s way.
“I think we were on the wrong end of a couple of decisions, not massive decisions, that went against us and they punished us,” the manager said.
“I don’t think there was much in the game. I was really proud of my players, they’ve done well.
“We’ve just been done with people being clinical against us.
“The lads did everything I asked. I asked them to make it into a cup tie and get in their faces and be competitive.
“It was a good game, both having a go. That first goal took the stuffing out of us. It killed us a bit.”
Elliott felt a foul should have been awarded to his team for an infringement on Davies in the build-up to County’s killer second goal, also questioning the penalty awarded to his own side.
He added: “I think it’s definitely a foul. I feel weak, I hate to be one of them managers who blame officials - but it’s a big decision at a big time.
“Everybody stopped and she’s let it go on.
“I don’ think it was a penalty. She’s tried to make up for a bad decision there. I said to their manager ‘it’s never been a penalty’.
“The scoreline didn’t reflect the match, but you wake up and it’s still 3-1 you have to accept it.”