New Wales defence coach Mike Forshaw has told his players they must improve their "poor" discipline to prevent Scotland wing Duhan van der Merwe leaving a "trail of destruction" in his wake this Saturday.
Wales endured a horrible first 40 minutes in Cardiff, finding themselves 27-3 down at the interval during their crushing Six Nations defeat to Ireland.
This was in no small part down to their shocking discipline with Wales conceding 15 penalties along with 33 missed tackles.
READ MORE: Alun Wyn Jones now fit to play against Scotland after HIA confusion
And Forshaw, who has only been in the job a matter of weeks, has already been reading the riot act.
"A poor first 20 minutes cost us," said Forshaw.
"Playing against a terrific team the last thing I wanted us to do is be defending lineouts five metres out in the first five minutes of the game.
"We conceded nine penalties in the first 20 minutes which cost us field position against a good side.
"You can't give away that number of penalties at this level, defending five metres lineouts against Ireland, who we know are a very good side.
"Offsides for me are a non-negotiable. It's a really poor penalty to give away because it's a controllable.
"That is something we need to fix up. Offside penalties, as I said to the lads, are just free runs for the opposition and we've got to tidy that area up pretty quickly at the start of the game on the weekend and not have any nonsense like that."
Forshaw will have his hands full this weekend trying to devise a plan to stop Scotland wrecking ball wing Duhan van der Merwe, whose try against England last weekend brought back memories of Jonah Lomu in his pomp.
And the former Sale Sharks coach insists Wales will have to be on their mettle to contain the likes of van der Merwe, Finn Russell, and Stuart Hogg.
What will happen in Wales v Scotland? Cast your vote now
"Without giving too much away if you watched how England played, they (Scotland) have a pretty dangerous back three," he said.
"Van der Merwe obviously, if you are going long and strong with your kicking game you have to be strong defensively because he is coming at you with some speed.
"He scored a wonder try at the weekend, probably one of the best tries I have ever seen.
"Hogg can hurt you. Then you have Finn Russell, who is called the Gambler, who will try things off the cuff.
"I have had experience of that coaching against Racing over the last few years.
"We have to bring them to the fight a bit more and not be giving them long and strong opportunities.
"The England tactic of going long was probably not great but having said that, there is a bit of X-factor in that back three.
"I don't know if Kevin (Sinfield) would be happy with that try they scored because he beat six defenders but he is a bloke who can hurt you.
"I have seen him (van der Merwe) when he was playing for Worcester in previous seasons and he has created something out of nothing and left a trail of destruction."
READ MORE:
Warren Gatland needs to go for broke and plan for World Cup with younger, new-look Wales team
Gatland must tear up Wales' front five, it's been the problem for years
Wales legend calls for team to be ripped up and eight changes made
Old Irish rival claims some Wales players 'not Test standard anymore'
New World Rugby rankings see Scotland reach highest ever position as Wales cast further adrift
