Wales discover what actually went wrong with substitute error against Fiji

Warren Gatland has explained how Sam Costelow ended up replacing Mason Grady during Wales' defeat to Fiji, rather than Ellis Bevan.

After Wales' 10th consecutive Test defeat on Sunday, Gatland revealed that scrum-half Bevan had been intended to replace Grady, after the wing was forced off injured in the first-half.

The change came after Gatland opted for a six-two split on the bench, that left Bevan and Costelow covering the entire backline from the replacement's pine.

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Now, Gatland has explained how an issue with the radio communication system led to the mix-up.

"Probably when I look at that myself, when I mentioned Ellis coming on, both of those players were an option," said Gatland. "Look, that replacement wasn’t an issue for us because Sam did a really good job, being thrown on the wing.

"We didn’t get the comms that came through the radio. Talking to the medics and staff, they said they delivered that message a couple of times.

"We had also delivered a message about the front-row getting on that they hadn’t received."

The communication system in place allows members of Wales' coaching group get messages down to members of staff on the sidelines. TV cameras showed Wales assistant coach Rob Howley appearing to try to send a message down via the radio before Costelow came on, but it's understood a number of different coaches deal with different members of staff via a number of channels.

However, it's understood that there was a system-wide issue on the weekend - the first time something like this had happened.

Costelow was brought on in the 17th minute for Grady, after the Cardiff back limped off with ankle injury that has ultimately ruled him out of the autumn campaign.

Coming on, the Scarlets fly-half was visibly confused over what position he would be assuming, seen speaking to Gareth Anscombe and Ben Thomas ahead of an attacking lineout.

Costelow spent 47 minutes on the wing, before Bevan replaced Anscombe - allowing Costelow to move to fly-half while the Cardiff scrum-half finished the game out wide.

Gatland revealed afterwards that the plan had been to bring on Bevan in place of Grady and added that he would "need to get the bottom" of how the mistake had happened.

It's understood that, even the day before the Fiji game, the plan had been for Bevan to cover the outside backs should any injuries occur - although Gatland now says that either option was fine with the Wales coaches.

Speaking about the need to go public with the mistake, former Wales dual-code international Jonathan Davies, in his WalesOnline column, said: "I don't know why Warren Gatland admitted they had sent on the wrong player to replace Mason Grady. He could have kept that in-house. If you've made a mistake, why expose it to the world?

"Surely they discussed that in the week? It's a professional environment and they've been in camp for a couple of weeks. Surely you know who will come on if someone gets injured. I don't know why they mentioned that."

Speaking about the criticism he's faced since revealing Bevan was the intended replacement, Gatland added: "Probably in hindsight, I’ve always tried to be as honest and transparent as possible.

"Maybe a lesson for me in the future is not to be honest. I was trying to make a point that we’d gone for a six-two split and had been caught early on with one of our wingers going down.

"So we had to make that substitution and we probably didn’t get the opportunity to discuss about what the replacement was . Both of them were options for us.

"Maybe if we’d got that message to come through, we might have put Ellis on. But it wasn’t a big issue for us. It wasn’t a problem with Sam going on and Ellis coming on later."