Samoa coach Stephen Betham admits discipline could cost his talented side at the World Cup but he demanded ahead of their first test against the United States on Sunday that referees treat them fairly.

Samoa are seeded to reach the quarter-finals from Pool B -- that also comprises two-time champions South Africa, Japan and Scotland. But Betham is forecasting a tight tussle with the Americans even though his side is packed with players playing in England and France.

Key to the Samoans chances of reaching the last eight for the third time will be them keeping their cool in the heat of battle, according to Betham. They have already lost veteran lock Kane Williamson for the opening game to finish a two match ban.

"Discipline is something we have worked hard on and the boys have talked about," said Betham on Friday.

Discpline "is one of those things we have to keep our focus on," he added.

"It will play a big part. The referees have tagged us and have perceptions of it, but we can't use it as an excuse.

"However, whatever they do to us we ask they see it the same way with our opposition.

"We are not going to complain we just want it done evenly and we will get on with the job."

The importance of keeping their cool is reflected in how tight previous matches against the Americans have been, with the Pacific islands team winning all four but never by more than seven points.

- US threat -

"The United States pose a great threat, a fortnight ago they trailed Australia (at Soldier Field, Chicago) by very little at half-time (14-10) and they hung in there (though they ended up losing 47-10)," said Betham.

"We have a lot of respect for them and we have to be on our game on Sunday because we are expecting a big match.

"All four previous games have been tight and I am not expecting anything different. We are focussed on what we can do, and we will try and minimalise any mistakes we may make."

Betham dismissed the form guide as being overwhelmingly in their favour despite having beaten virtually the same USA team 21-16 in July in the Pacific Nations Cup. The Americans showed great spirit then to come back from 21-3 down.

"The Pacific Nations is a different game," said Betham, who will look to the Pisi brothers, Ken on the wing and Tusi at fly-half, to make their experience felt at the highest level.

"In the World Cup every game is a championship game. This is where you gauge yourself on the world stage.

"Every country has brought their best team and you can't afford a lapse of concentration.

"It is very important we start well, which we havent in our last couple of games. We have the belief that if we start well everything will fall into place."

For the Americans much will depend on how talented Ireland-born fly-half AJ MacGinty -- he only made his debut in the Samoa game and scored 11 points -- takes to the hotbed atmosphere of a World Cup and if he can punish with his boot any ill disciplne by the Samoans.

MacGinty, whose alma mater is Blackrock College, the same as iconic Irish centre Brian O'Driscoll, has some talented backs outside him, no more so than Zimabwe-born wing Takudzwa Ngwenya, whose pace may have slowed over the years but will still punish slack defending.

Source: AFP