Ole Gunnar Solskjaer backed Bruno Fernandes as Manchester United's penalty taker after the playmaker's rare miss helped Aston Villa to victory at Old Trafford.
Defender Kortney Hause gave Villa the lead in the 88th minute with a near-post header only to handle the ball moments later, giving United the chance to salvage a point.
But Fernandes, who had scored 21 of his previous 22 penalties for United, sent the ball high over the bar as Cristiano Ronaldo looked on.
Villa held on for a 1-0 victory, handing United their second loss of the week at Old Trafford – after a Carabao Cup defeat by West Ham – and a third in four games.
Solskjaer was annoyed by the reaction of Villa's players to the decision – including keeper Emi Martinez seemingly suggesting Ronaldo should take the penalty – but backed Fernandes and declined to say whether Ronaldo might be given the opportunity next time United are awarded a spot-kick.
He said: "Sometimes it just doesn't go your way. Bruno is such a good penalty taker and today you would have backed him with your mortgage I would guess.
"What I didn't like was the way they crowded the referee and the penalty spot and Bruno and tried to affect him. It clearly worked but that's not great to see.
"Bruno has been excellent and Cristiano is probably the one who has scored the most penalties in world football. We've got great takers and it's a missed opportunity for us to get a point."
There were opportunities for both sides in an open game but Villa were certainly worthy of at least a point, with Matt Targett and Ollie Watkins also having excellent chances to score.
The closest United came apart from the penalty was a header from Paul Pogba just before half-time that flew wide.
Solskjaer said: "When we got to the final decision, the final execution, the quality in the pass or the shot or the decision wasn't good enough to get goals."
The United boss argued Hause's goal should not have stood because of the positioning of Watkins.
"You see the inconsistencies again with VAR and the decision-making," he said. "Watkins is touching David (De Gea) as the header has gone in. It's offside or it's a foul.
"The linesman did well, they called it into VAR, but they turned it down and it was a goal so bad decisions again unfortunately.
"We should have slowed the game down at times. We didn't have enough control even though we had 60 per cent possession and 30 shots or whatever."
Solskjaer, meanwhile, must anxiously await the results of scans for England defenders Luke Shaw and Harry Maguire, who were both forced off with injuries.
It was Villa's first victory over United since 2009 and only their second at Old Trafford since 1983, making it a very big day for manager Dean Smith.
He said: "As everybody knows, we have had an awful lot of suffering as Villa fans at this stadium but I think we've been close in the last couple of years.
"People will look at it and say it is a big win but for me it is more a big performance.
"I thought we deserved the win. I thought we had the bigger chances. We were aggressive in the way we played against a front four of Ronaldo, Pogba, Fernandes and Greenwood.
"There is an awful lot of belief. I felt we have recruited well since Jack (Grealish) has gone and the performance levels have been there. We had an indifferent start but there were reasons for that."
