A VAR check by Darren England in Stockley Park occurred, with screens inside the stadium informing supporters, but play was able to quickly resume with the effort remaining offside.

Referees’ body PGMOL has since acknowledged a “significant human error” occurred and that VAR “failed to intervene” to prevent the error.

The PA news agency understands that the VAR drew the lines to check for offside and followed the process correctly.

But, in what sources described as a momentary lapse of concentration, England lost focus of the initial on-field decision, meaning his confirmation resulted in a ‘check complete’ instead of intervening and awarding Diaz’s effort as intended.

Liverpool went on to finish the match with nine men and suffered stoppage-time heartbreak when Joel Matip deflected Pedro Porro’s cross into his own net in the sixth minute of stoppage time, but the post-match discussions focused on the crucial first-half error.

“Who does that help now? We had that situation in the Wolves-Man United game. Did Wolves get the points? No,” Klopp reflected when informed of the PGMOL statement.

We will not get points for it so it doesn’t help. Nobody expects 100 per cent right decisions on field but we all thought when VAR comes in that it might make things easier.

“I don’t know why the people…are they that much under pressure? Today the decision was made really quick I would say for that goal. It changed the momentum of the game, so that’s how it is.”

After a breathless start at Tottenham Hotspur Stadium, Liverpool were reduced to 10 men in the 26th minute when Curtis Jones was sent off following a VAR review.

Jones caught Yves Bissouma with a high, studs-up tackle on his shin that initially earned him a yellow card but referee Simon Hooper upgraded the decision to a red card after he used the pitchside monitor to review the incident.

Diaz found the net six minutes later, but after it was ruled out Tottenham went ahead when captain Son Heung-min tapped home from Richarlison’s centre in the 36th minute.

Cody Gakpo levelled for Liverpool on the verge of half-time but Klopp’s problems mounted when Diogo Jota was dismissed midway through the second half following two fouls on Destiny Udogie in quick succession.

It meant Liverpool had to play the final 21 minutes in north London with nine men and their stubborn resistance was finally broken when Porro’s dangerous cross was diverted past Alisson by Matip.

Klopp added: “I told the boys after the game I am super proud and especially with 10 men they were really good. They did everything that is necessary and on top of that we were courageous.

“I don’t think there is anything to say about the offside goal. I knew at half-time.

“In the first moment I thought it was clear offside but then it is right to think they have a better view and at half-time we knew with normal pictures. Easy to see, no offside.

“But I am pretty sure whoever did make that decision did not make it on purpose. It didn’t take extremely long to come to the conclusion, that is a bit strange, but someone else has to clarify that.”

Tottenham head coach Ange Postecoglou, meanwhile, was happy to accept the rub of the green with the Diaz ruled out effort but highlighted that VAR will never be “errorless” after he watched his team’s unbeaten record stretch to seven matches in the Premier League.

He said: “I think I’m on record as saying that I’ve never really been a fan of it since it came in. Not for any other reason than I think that it complicates areas of the game that I thought were pretty clear in the past.

“We used to understand that errors were part of the game, including officiating errors. You’d have to cop it and some people would cop it better than others but that was part of the game.

“The game is littered with historical refereeing decisions that weren’t right but we all accepted it that it was part of the game because we’re dealing with human beings.

“I think that people are under the misconception that VAR is going to be errorless.

“So much of our game isn’t factual. It’s down to interpretation and they’re still human beings. They’re going to make mistakes the same way managers make mistakes, the same way players make mistakes.

“When you put such a high bar on something it invariably is going to fail, so if people are thinking that VAR is going to be something that at some point that is perfect, that’s never going to happen.”