Diaz was adjudged to be offside in the first half of the controversial game in which Liverpool eventually lost 2-1.
But the Liverpool attacker looked to be clearly onside, and with no official lines being drawn to show supporters, the PGMOL have now admitted that the VAR official, Darren England, failed to intervene.
PGMOL acknowledge a significant human error occurred during the first half of Tottenham Hotspur v Liverpool.
The goal by Luiz Diaz was disallowed for offside by the on-field team of match officials.
This was a clear and obvious factual error and should have resulted in the goal being awarded through VAR intervention, however, the VAR failed to intervene.
PGMOL will conduct a full review into the circumstances which led to the error.
Speaking on Sky Sports post-match, Gary Neville said that the VAR, Darren England, said “check complete” in the referees’ earpiece after the incident.
"Something doesn't feel right."
Neville said: “It was all too quick, it wasn’t right.”
“We will not get points for it, so it doesn’t help.
“Nobody expects 100 percent right decisions on field, but I think we all thought when VAR comes in, it might make things easier.
“I don’t know why people in VAR, are they that much under pressure, the decision was made really quick I would say for that goal.”
“The VAR should be absolutely clear and obvious with everything they’re deciding on. I’ve seen the still back, I think on live TV there were no lines being shown.
“It’s all a bit strange, I don’t know who was in the VAR room and making that decision. It’s not a good thing, it doesn’t look well either. It is what it is, we lost.”