Livewire Wallabies halfback Tate McDermott will miss their crunch Rugby World Cup pool clash with Fiji after he was felled making a tackle in their opening win over Georgia.

The Australians got off to a flying start with a 35-15 victory at Stade de France on Saturday (Sunday AEST) but their next challenge from Fiji, who downed England in a tournament warm-up match, is far more formidable.

It's a key match in the pool with the island nation, Wales and Australia vying for the two quarter-final spots.

The task will be made tougher without McDermott, with the tempo of the match slowing when he was replaced by veteran Nic White, who Jones is expected to turn to in their game next Sunday (Monday AEST) in Saint-Etienne.

McDermott appeared to be momentarily knocked out late in the first half after his head collided with a Georgian knee.

Referee Luke Pearce immediately checked on the No.9 as he lay on turf before McDermott received medical treatment and he walked gingerly from the field, supported by the Wallabies doctor Sharron Flahive.

He was seen with the team out on the field post-match.

Rated a grade one concussion, under protocols McDermott will have to stand down for 12 days ruling him out of Fiji.

The vice-captain could return to face Wales in Lyon, which is in 15 days time.

Strike centre Samu Kerevi also left the field in the 42nd minute but Jones said it was a planned move, given his string of injuries, including an ACL and hand issue.

"Samu we always planned to play 40 ... we wanted to give him a hit-out," Jones said.

"He hasn't played since Dunedin so we needed to give him some time but he's come back from from a number of number of injuries so the plan was to get him ready for Fiji next week.

"It's obviously for him and for us an important game.

"Playing against your mother country is pretty special, so we want to give him the best opportunity to be ready."