Robin McBryde says securing the Six Nations title against England would prompt an outpouring of joy to rival Wales' famous Wembley win of 1999.
The sides meet under the roof at what will be a packed Millennium Stadium (kick-off 1700 GMT), with both harbouring ambitions of lifting the championship trophy.
Stuart Lancaster's England will secure their first Grand Slam in a decade should they emerge victorious.
But Wales can retain the championship crown - an achievement they last managed in 1979 - if they can win with a margin of seven points and stay ahead in the overall tournament try-count.
A win by eight points or more would render try count - a tally in which Wales hold an advantage of two - irrelevant.
The last time the two nations locked horns with a Grand Slam on the line was back in 1999 on the final weekend of the final Five Nations Championship.
That day an immaculate kicking display from Neil Jenkins - now part of the Wales backroom staff - and Scott Gibbs' late try sealed an improbable 32-31 win.
The victory has gone down in Welsh rugby folklore, and assistant coach McBryde knows derailing the English chariot again will spark wild celebrations on a par with those of 14 years ago.
He said: "I think it would have the same effect as 1999.
"The build up has been more of a slowburner this time, if you look at the championship from a Welsh perspective.
"From our poor opening half against Ireland we have gained momentum.
"Conditions in our subsequent games haven't favoured attacking rugby and I would not imagine we would shift a lot of DVDs of the tournament if we are successful.
"But something would erupt in Cardiff if we do it."
He added: "Stopping England is a part of it. When you look at the fixture list and see England last, irrespective of other games, you know you end up with a big game.
"The fact England are in the situation they are in, and we find ourselves with an opportunity, there is no need to fuel the fire any further."
Wales have won five consecutive away games in the Six Nations, but have lost all five of their home fixtures this season.
McBryde does not believe their poor run of form in Cardiff will harm Welsh chances.
"I don't think it will have an effect on this occasion," he said.
"It has been a while since we played at home and the feeling on the bus on the way to training was we feel comfortable here, we know what we are facing.
"We know the police escort and the crowds on the way to the ground are on our side, so we will feel comfortable, like putting on an old shoe and getting ready for battle."
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