Carrick's weak effort was saved by Burnley keeper Brian Jensen, who admitted he was "surprised" that the midfielder was chosen to take then penalty.
"I think we'd have won the game if we'd scored that," said Ferguson about the penalty miss.
"We'd have composed ourselves and won, I think. Instead, in the second half we got harried with our passes and made a couple of bad decisions. That can happen.
"We should have done more with the chances we had and the possession we had. But in fairness to Burnley they had a good spell too and caused us a lot of problems."
Ferguson went on to admit that a disjointed looking United had performed poorly, but did find time to give the hosts a patronising ruffle of the hair for their display.
"We usually take our time to get going" he said.
"Sometimes it's October before we get into our best form. But we shouldn't be losing these games. It was a bad performance and we should have done more with the chances and the possession we had.
"You have to give credit to Burnley. It's a great night for them. You can't deny them their victory. They worked their socks off and the fans were fantastic."
