"It's not him to blame, he's been fantastic for us and won us many games and many points. We were still in a winning position, so it's nothing to do with the penalty that lost us the game today. It was individual errors at set-pieces that have cost us."
The defeat saw United drop points for the first time in a hectic Christmas period, and Fletcher is already looking ahead to Birmingham's visit to Old Trafford on New Year's Day.
"Every time you drop points or lose, you have to pick yourself up and go on another winning run," he said. "We wanted to get through the Christmas period with maximum points and put pressure on the teams below us, but unfortunately that's not happened.
"We've got to pick ourselves up for Birmingham now and get three points and go on another winning run. We can't wait for that game to come now."