Ole Gunnar Solskjaer says Juan Mata trusted Fred to take a late free-kick against Manchester City on Wednesday night.
United needed one goal to send the Carabao Cup semi-final to penalties and had a good chance to score when Harry Maguire was fouled 20 yards from goal.
Many questioned why Mata didn't take the free-kick, which Fred blasted into the wall, but Solskjaer says it was the Spaniard himself who made the decision.
“Juan is the best one when he feels like it," admitted the manager to journalists. “But they practiced yesterday and Juan told me that Fred was unbelievable in training.
“He scored six or seven on the bounce apparently, and they both felt this was his moment. That was the decision they made there and then. Probably the right decision, but it didn't work out well."