2003 Rugby World Cup winner Josh Lewsey believes the nation with the greatest "mental edge" will win the tournament in England later this year.
Lewsey, who lifted the Cup with England, is now head of rugby at the Welsh Rugby Union and knows his fair share about pressure on the big stage.
And he is confident that despite all the hard work that is going in on the training field, it will be the top two inches that decides this year's winner.
"There is no difference in how strong they (teams) are or skill-wise, but on the biggest stage when it matters most, big-match players deliver," he told Press Association Sport.
"When you get to a global stage it can be quite intimidating, so that's why mental edge is the one quality that distinguishes winners and good players from champions."
Lewsey continued by backing at least one northern hemisphere team to reach the World Cup final, despite just one of those, England, winning the coveted trophy in its seven previous tournaments.
"You have got to have that belief if you are going to win tournaments and win trophies, and let's hope a northern hemisphere team does it again this year," he added.
"Historically, the southern hemisphere have clearly led the way. The way the draw has worked it's likely at least one northern-hemisphere team will get to the final, but we shall see.
"There are some proper teams there, and it makes for a fantastic occasion."