Ole Gunnar Solskjaer felt inaction from the VAR cost Manchester United in their defeat to Aston Villa on Saturday.
United lost 1-0 at Old Trafford to Kortney Hause's header in the 88th minute, although Bruno Fernandes missed a stoppage-time penalty that would have sent the home side top.
Solskjaer's side were poor, with only four of their 28 attempts hitting the target – their most shots without scoring in a league game for five years (38 against Burnley in October 2016).
But the manager was not happy with the nature of Hause's winner at the other end.
Solskjaer highlighted Ollie Watkins' position close to David de Gea in an offside position and revealed a discussion with officials indicated the VAR was to blame.
"We started the game well, aggressive, good on transition, going forward quickly," he told MUTV. "The decision-making, execution in the last third wasn't the best, and that cost us today.
"And decision-making on VAR again cost us again.
"Unfortunately, I've got to say it: it's offside. The goal, as Hause is heading it, Watkins is actually touching David, he's impeding him.
"I can't see the consistency anywhere in this VAR decision-making.
"They've come out in the corridor, and I've asked them for an explanation. The linesman flagged it up with VAR and definitely VAR has gone wrong again."
It would not have mattered had Fernandes taken his chance, having scored 21 of his previous 22 penalties in a United shirt.
Solskjaer felt pressure built on the midfielder as Villa players surrounded him in the 93rd minute for what was United's fourth-latest Premier League spot-kick miss.
"I didn't like the way they crowded Bruno, the penalty spot, the referee, all that malarkey," he said.
"Bruno's very strong mentally normally and unfortunately today it just didn't go in."
United had already endured a difficult day prior to the late drama, with both Luke Shaw and Harry Maguire substituted due to injuries.
Asked about their status ahead of a big week, with Villarreal visiting in the Champions League, Solskjaer said: "I can't tell you, I don't know. We'll have to wait a couple of days and see how they are."