The green light from the video referee even left the Melbourne veteran stunned.
'I've been playing for 15 and a half years but I didn't know that. I honestly thought I knocked on," Slater told Channel Nine at halftime.
Despite the massive uproar, NRL referees boss Bernard Sutton says the bunker was right to award the try.
"The on-field official asked the bunker to confirm that Slater had drop kicked the ball and not knocked on," Sutton said.
"For this to be a drop kick the ball must be intentionally released from the hands and then kicked immediately after it rebounds from the ground.
"It's important to note that a drop kick can occur at any point during a match and does not have to be an attempt at a field goal.
"With that in mind the bunker correctly confirmed the live decision of try."
As much as it may gall some fans, Sutton is correct. The 'Rugby League Laws od the Game Interntional Level' are the laws upon which the game is adjudicated.
In those laws a 'Drop Kick' is defined as 'a kick whereby the ball is dropped from the hands (or hand) and is kicked immediately it rebounds from the ground.'
The intent of the kicker is not an issue.
Even Melbourne coach Craig Bellamy thought Slater had knocked on.
"I thought to be quite honest it was probably a dropped ball," he said.
"But I wouldn't put my house on it because I didn't know the rule.
"I probably would have thought if you were doing a drop kick you would be looking for a field goal but he certainly wasn't trying to kick a field goal.
"If I was sitting up in the box I probably would have went red."
Brisbane coach Wayne Bennett said the NRL had now set a precedent.
"That's a game changer if that's to be the standard going forward because it was never intended to be a drop kick and the ball hit the ground," he said.
"So what are we saying now? If we knock the ball on and still kick at it it's a drop kick?
"He definitely lost the ball.
"If we drop a ball and all of a sudden kick at it can we get away with a knock on?"
