Wales boss Warren Gatland has billed Sunday's RBS 6 Nations showdown between England and Wales as a big "psychological" game ahead of the 2015 World Cup.
This weekend's encounter will keep one team in the Six Nations title race and effectively end silverware hopes of the other.
But it will also provide an early pointer towards next year's World Cup, with England, Wales and Australia all drawn in the same pool.
"It's a big game psychologically for both teams because we have to go there (Twickenham) next year as well. That's going to be even bigger than this Sunday," said Gatland, who has recalled fit-again centre Jonathan Davies and lock Alun-Wyn Jones to his starting XV.
"We have two big games at Twickenham in the World Cup against England and Australia.
"If we can win on Sunday, that is four in a row (against England) and if we then win the Six Nations as well, you start having a few doubts.
"The (Wales) starting XV won't be too far off 1,000 caps when it comes to the World Cup, and it won't be too far off its peak in terms of the age profile."
Regarding his team selection for this weekend, Gatland said it was not a difficult decision to recall British and Irish Lions star Davies.
Davies has been sidelined from Test rugby for four months and has seen just 105 minutes of competitive action for the Scarlets since suffering a torn pectoral muscle during Wales' opening autumn series defeat by South Africa on November 9.
But the 25-year-old centre, a key performer in the Lions' Test series triumph against Australia last summer, returns to resume his powerful midfield partnership with Jamie Roberts.
With Davies back, George North, who deputised in the number 13 shirt against France last month, reverts to his familiar wing position, with Liam Williams dropping out.
"He (Davies) has been training really hard," Gatland added. "He is a world-class player, so it wasn't difficult for us to make that call.
"Jonathan has been doing a lot of training in the last five weeks. He has probably been doing too much really. In terms of being fit, he is really sharp at the moment."
Four teams - Ireland, England, Wales and France - are currently locked on four points at the top of the Six Nations table.
Ireland's superior points difference means they are favourites to lift the title, although their final game on March 15 is against France in Paris.
The losers at Twickenham will effectively be out of title contention, which further raises the stakes for the 125th meeting between two fierce rivals. The countries are currently locked on 56 wins each, with 12 draws.
Wales, though, could have a mental edge after swamping England by a record 30-3 scoreline in Cardiff last season, giving Gatland's men the title and destroying English Grand Slam hopes.
"They (England) look like a young team that is playing with a little confidence and self-belief, and that's what makes them dangerous," Gatland said.
"Part of my job for this week is to build the players up to have the self-belief that we are good enough to go to Twickenham and win.
"It has definitely been a bridge too far for a number of Welsh players in the past, but we are not thinking like that. If we play well enough on the day then we are good enough to win.
"They (England) are all saying they have learnt some pretty harsh lessons from last year. All the talk is that the boys have turned into men and they have grown up and learned. Time will tell, won't it? We will see on Sunday.
"It's a big Test for all of us. These big occasions are what we all play and train for and put in the effort that people don't see.
"You get excited about playing in a full stadium with a lot at stake. We are really excited about going up there on Sunday as underdogs."
Responding to comments, meanwhile, by England wing Jack Nowell that the emotion Wales feel towards their next Six Nations opponents is one of "hate", Wales captain Sam Warburton said: "I don't think the boys talk about England games like that.
"They love it because the atmosphere is always so good. You sense the anticipation of the fans all week. The fans love it and we definitely feed off that.
"They are massive games to play in but hate is a very strong word."