When Nick Phipps hears people suggest the Wallabies' campaign for the World Cup in England began with their departure from Australia last Saturday, his mind turns back almost six months.

For the Waratahs halfback, the campaign really began in "mid-March or April", when coach Michael Cheika began holding meetings of inside backs in contention for the 31-man World Cup squad.

Those meetings covered the various plays to be used and specific core calls for them – all of which the halfbacks, five-eighths and inside centres would be required to know.

"I wouldn't say it is just starting now that we are away from Australia," Phipps said on Wednesday in the US, as the Wallabies prepare for their last game before the tournament, against the US Eagles at Soldier Field in Chicago on Saturday.

"I still remember the first callers' meetings ... when seven or eight of us from around the country were coming in [to Sydney] and playing in those nine, 10 and 12 positions.

"It gave us an opportunity to nut out a lot of the plays … the core calls, so when we came into camp we didn't spend ages getting to know them.

"The nine, 10 and 12 could take early control of that straight away, and start to filter that through the group."

Phipps has relished the days at Notre Dame University in Indiana, where the Wallabies have been training in sweltering heat and humidity.

"We have been doing a lot of work because we know how good the US Eagles are and how well they have been performing lately," he said.

It did not surprise Phipps to hear Eagles coach Mike Tolkin say his side, while ranked 16th in the world, would not be intimidated by the No.2-ranked Wallabies.

"They never would be. They haven't been playing like they are 16th in the world," said Phipps, adding the Wallabies watched video of the Eagles' 24-19 loss to English club Harlequins on the weekend.

"They are going really well. They should cause a couple of upsets at the World Cup."

Asked where major threats exist in the Eagles, Phipps said: "They have some very big, dominant forwards. They have got some really big, tall timber in the second row and they have got a really good back row that are on the ball.

"They also have got a couple of centres that are hard runners and are quite skilful in the offload area as well. They have got threats all around the park.

"Their nine and 10 are quite smart players. They direct the troops well and have a great kicking game, and you can see that they are the real quarter-backs of their squad."