According to Nel, Garces should have penalised the All Blacks skipper for joining the lineout from the halfback position.
"I'm not saying that's the reason the 'Boks lost but if you look at it again it's a try that should have at least been reviewed and probably not allowed," Nel told Radiosport.
"If you look at the try again, Richie takes up a position at halfback as the receiver and the receiver can't join the lineout until the ball has left the hooker's hands. If you look at the slow-motion, Richie moves inside, he's not two metres away as the law says, he's only a metre away and joins the lineout from an offside position."
However Lawrence, who copped flak from South African fans after his referee performance in South Africa's quarter-final defeat to Australia at the 2011 World Cup, told Radiosport that the try could not have been referred to the TMO and backed Garces.
"He [Nel] raises a valid discussion. He says it's a bit clearer on slow-motion, well the referee doesn't have slow-motion on the field. So I'm not convinced it's clear and obviously an issue around where Richie was standing and where he left.
"I'm also not convinced it could have been referred to the TMO to check because my understanding of the TMO process is an instant like that can't be referred and checked.
"Checking whether the receiver was back two metres and did he leave a split second early or was he fine, to my knowledge that can't be referred to the TMO. That's a decision that the referee makes live in the moment," Lawrence said.
Nel said he asked a number of South African referees who said it shouldn't have been awarded as a try.
"I checked with two or three referees on it as well and they all agreed at the very least it should have been reviewed. Most of them said if they were refereeing it they wouldn't have given the try and probably a penalty to the Springboks."
"It happens very quickly. I do understand they miss these things but the ref should have been cognitive on where Richie was standing."
Nel explained the laws in an article for Supersport.
"According to World Rugby law 19.8.i - (i) Where the receiver must stand. If a team uses a receiver, then that player, must be positioned at least 2m back from teammates in the lineout, and between the 5m and 15m lines, until the lineout begins. Once the lineout has commenced, the receiver may move into the lineout and may perform all actions available to players in the lineout and is liable to related sanctions," Nel reports.
"Read with law 19.9 (a) - which says "The lineout begins when the ball leaves the hands of the player throwing it in", it is clear that McCaw has moved before the ball has left the hooker's hands, and since he is not 2 metres back, has all the advantage from an illegal position," he added.
Nel also claimed that Garces could have also penalised the All Blacks for lifting no.8 Kieran Read before the ball was thrown, something that often ignored by referees at lineout time.
Former South African referee Jonathan Kaplan wrote on his blog Rate the ref that McCaw made an illegal move.
"As a receiver, he has to stand two metres away from the lineout. It is questionable whether he was. Moreover he cannot move into the lineout to receive the ball until the ball has left the hands of the thrower," Kaplan wrote.
"It is clear he does start moving before the ball has left the hands of the hooker. The referee never had a clue what was going on. One can see with his body language, that he [Garces] was quite happy to award the try."
Kaplan also wrote that Schalk Burger let South Africa down by not contesting the play.
"Where was our leadership to insist that this important and defining score be verified," Kaplan wrote.
Yesterday Read revealed that the winning lineout move was something he came up with earlier in the week.
"I came up with it," Read said.
"You look at it each week, how teams defend. It's pretty nice when it comes off. It doesn't normally come off but when it does it's a good feeling."
Read admitted he could not reveal too much ahead of the Rugby World Cup later in the year.
"I saw a little opportunity but I can't be giving too much away. As you know there are some important games later in the year where we might need something.
"We've got a few up our sleeve when we need them. We'll just have to hang on to them for the rest of the year."
While Tony Woodcock's famous lineout try in the 2011 World Cup final against France came from a move called the "teabag", Read would not divulge the nickname for Sunday's successful play.
"I'm not sure we can elaborate on a name just yet. I'm sure you guys [the media] can come up with something nice," he said.
