Wellington - Reigning Rugby World Cup champions South Africa and contenders Australia open their campaigns later on Sunday while the United States will commemorate the 10th anniversary of the September 11 attacks before taking on Ireland.
The entire U.S. squad will attend a morning church service, both sides will wear black armbands and the crowd will be asked to observe a period of silence to remember the attacks on New York and Washington in which nearly 3 000 people died.
"You can say a lot of things now, but in the heat of the moment the emotion is going to hit," U.S. prop Mike MacDonald said earlier this week. "It will hit people in different ways."
MacDonald will earn his record 63rd test cap for the American side at Stadium Taranaki in New Plymouth, surpassing the 62 he had shared with the now retired Luke Gross, and he felt the timing was poignant.
"I'm ecstatic it's happening when it is. It's a great occasion, being the 10th anniversary of 9/11 and the first game of the World Cup. It really means a lot for me that it has come at this time."
Tri-Nations champions Australia also start their World Cup with a match against Italy at North Harbour Stadium.
"Critically it's the start to the tournament and the nature of tournament play is 'you do or you die'," Wallabies coach Robbie Deans said. "That's what we've got in front of us."
The final match of the day pits the world champion Springboks against Wales in a clash that is expected to be crucial for the future direction of Pool D with the forecasted bad weather likely to favour South Africa's grinding game plan.
"Without doubt the weather is going to be a factor tomorrow night, but we can't be overly concerned with it," Wales assistant coach Robin McBryde said.