Lock Luke Charteris believes Wales' gruelling World Cup preparations can give them a crucial edge when they meet South Africa in their Pool D opener.
The Newport Gwent Dragons second row has made head coach Warren Gatland's 30-man squad for the global showpiece in New Zealand, with Wales drawn in the tournament's toughest pool along with the Springboks, Samoa, Fiji and Namibia.
"We can go in (to the South Africa game) with a lot of confidence in our conditioning and physicality," he said. "In years gone by we have always competed with the southern hemisphere teams but faded in last 20 minutes, and we want to change that."
Pessimists within the Welsh game are fearful of there being another first-round exit to follow similar failures in 1991, 1995 and 2007, with the games against the South Sea Island nations being looked upon as potential stumbling blocks.
But Gatland and company begin their campaign against the reigning champions in Wellington on September 11, with confidence buoyed by warm-up wins over England and Argentina.
Charteris added: "The massive confidence boost with our conditioning is now we know we can compete with these teams over 80 minutes.
"We know it does not matter how well you play or how close you get, if you lose, you lose and you feel it.
"It will not matter if we win by one point or 20 points, it's a World Cup and you have to get the win.
"Starting with South Africa, they are a big scalp, and if we get a good win there it will give us confidence for three other tough games.
"If we do that we can win the pool and that would set us up well for the quarters."