Neil Jenkins believes Wales will be playing for second place in the Guinness Six Nations if they lose to title favourites England next week.
The two remaining unbeaten teams in this season's tournament will go head to head at Cardiff's Principality Stadium.
And a third successive Six Nations win for England would leave them in control of the championship, underlined by their remaining two games being against Twickenham visitors Italy and Scotland.
"No disrespect to Scotland, who are a very good side and have done a lot of good things over the last year or so, but playing England at Twickenham is a big ask for any team," Wales skills coach Jenkins said.
"The reality for us is it's a game we need to win to give us a chance of winning the title.
"No disrespect, because I hope both Scotland and Italy do turn up at Twickenham and play exceptionally well, but the reality is if we lose we would be playing for second.
"As a Welshman, it's not far off being the be-all and end-all type of game. That's what it is for us.
"I think the emotions are pretty high at the moment, and we are still a week-and-a-half away from the game. We are under no illusions about what's coming.
"We know we need to play better than we have in the two games we've played so far.
"We haven't really fired a shot yet.
"If you can't get ready for a game like this then you are better off sat with me on the sidelines. It is a game I've no doubt we will be be ready for."
England head coach Eddie Jones followed up his team's 44-8 destruction of France last weekend by describing Warren Gatland's team – currently unbeaten in 11 games – as "the greatest Welsh side ever" and that the Principality Stadium "has never been a fortress for me."
But Jenkins added: "I'm not really bothered what he says, to be honest. It's up to Eddie what he says.
"He's got an opinion and he is entitled to that. It might not be intimidating for England.
"They've obviously won there the last few times they've played there, so it's probably not a fortress for them. Maybe he's right in saying what he's saying.
"We are just looking forward to the game and we aren't bothered by what Eddie says.
"He is a fantastic coach, has done a fantastic job with England, and has done throughout his career. Whatever will be said will be said.
"I don't think it will have much bearing on the game."
