The goal from the Liverpool forward would have been the game's opener, but things quickly got turned upside down for the Reds in a 2-1 defeat.
A statement from the organisation an hour after the match had finished read: "PGMOL acknowledge a significant human error during the first half of Tottenham Hotspur v Liverpool.
"The goal by Luis 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.
"PGMOL will be immediately contacting Liverpool at the conclusion of the fixture to acknowledge the error."
read more on liverpool
Tottenham seal last minute win against nine-man Liverpool after VAR controversy
'Needs an explanation' - Neville and Redknapp baffled by lack of lines for Diaz offside
Shortly after the goal was ruled out, Heung-min Son opened the scoring against a ten-man Liverpool side who had already seen Curtis Jones seen off.
Cody Gakpo equalised before the break, but after being reduced to nine men through a further controversial call on Diogo Jota, Liverpool eventually succumbed to defeat when Joel Matip scored a stoppage time own-goal.
Speaking before hearing the statement, Liverpool manager Jurgen Klopp said: "I've never seen a game like this with the most unfair circumstances.
"It was crazy with the decisions, and how we dealt with it, how we stayed in the game, how we fought, and then we scored an own-goal, it's really tough to take.
Most read in Football
Tottenham 2-1 Liverpool LIVE REACTION: Spurs seal last-gasp win over nine-men Reds
'Needs an explanation' - Neville and Redknapp baffled by lack of lines for Diaz offside
Jones given straight red for 'leg-breaker' but Neville says wrong call will 'ruin game'
#TenHagOut trends as Man United fall to defeat against Crystal Palace
"The offside goal, that is not offside when you see it, they drew their lines wrong.
"The ball is between Mo's legs, they drew the line wrong and didn't judge the moment when Mo passed the ball right.
"It is so tough to deal with it."
Later speaking to the media, Klopp was given the statement and admitted that it didn't help.
"Wolves got a similar statement or apology, but didn't get the points against [Manchester] United, and we will not get anything out of that today so it doesn't help," he said.
"We all have to work together so we make the right decisions and I'm pretty sure no one is making incorrect decisions on purpose, but it's still happening and I don't know why."