Wayne Pivac: Aaron Shingler yellow card was avoidable - Scarlets coach

Scarlets coach Wayne Pivac says more experienced referees should be in charge of derby games following the decision to sin-bin Aaron Shingler.

The Scarlets flanker was shown a yellow card by referee Lloyd Linton during their 26-15 victory over Cardiff Blues despite being tackled without the ball by his brother Steven, a fly-half for Blues.

Pivac insists the scenario should not have happened in a high profile match.

"You need an experienced TMO," he said.

"You need someone experienced who is going to have the ability to step in and help him on the run and I don't think that happened."

Scottish referee Linton is in his fourth season officiating in the Pro12.

Blues head coach Danny Wilson said there were a number of "talking points" during Friday's match. and felt his side should have been awarded a penalty try.

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Wilson also said after Pro12 derby matches should be controlled by experienced referees, a view shared by New Zealander Pivac.

"I understand the reasoning, they've got to go in at some stage," Pivac told BBC Radio Wales Sport.

"All he had to do was let that ball go out then go and ask the question upstairs then go back to the line out once he got the answer.

"So that was disappointing to think that everybody, the crowds, the coaches had to go through that passage of time and number of scrums.

"They can talk about penalty tries as much as they like there was no penalty try there. There shouldn't have been a scrum in the first place."