MELBOURNE should have been awarded a free kick after Adelaide defender Nick Murray's last-minute handball across the boundary line in the Crows' one-point win over the Demons at Adelaide Oval.
The free kick would have given the Demons a shot at goal in the dying seconds of the game. A behind would have tied the scores, while a goal would have put the previously undefeated Demons in front.
Instead, the umpire called for a boundary throw-in and Adelaide managed to prevent Melbourne from scoring at all, holding on for a famous victory.
The AFL revealed its decision on Monday night, saying: "It was the view of the umpire in real-time, that from his angle there was a player in the vicinity and, as such, decided to call a throw-in.
"Upon video review, it was deemed the player did not display sufficient intent to keep the ball in play."
Melbourne coach Simon Goodwin was diplomatic after the game when asked about the decision.
"It (deliberate out-of-bounds) is still one of those areas that we are still finding our way as a game," Goodwin said, refusing to be drawn further.
The day after the game, Adelaide coach Matthew Nicks said he was relieved that the Crows were playing at home in such a nail-biting finish.
"I had a chat to Nick Murray after the game and asked what was going through his mind, this is a guy who has played less than 10 games, but his actual intention was to handball to grass," Nicks told 3AW radio on Sunday.
"There are so many decisions across the game that we could look at, that could go one way or the other … that is footy.
"But I do understand why some people would be reasonably upset at this point in time.
"I think the fact we are playing a home game, thank goodness it wasn't the week prior at West Coast, that's why we play home and away, that's why we value our supporters and members that get there and there is 50 thousand cheering for us and not screaming for a deliberate out of bounds."
It is the third time the AFL has conceded a crucial umpiring error that has cost a team a possible match-winning shot at goal this season.
In round two, Zac Bailey should have been rewarded with a holding-the-ball free kick at the end of Brisbane's defeat to Geelong.
In round seven, Jeremy Cameron should have been awarded a mark deep in attack during the final seconds of the Cats' loss to Sydney.
On all three occasions, the team visiting from interstate has been on the wrong end of the decision.