Young Australia flyhalf Berrick Barnes has spoken of his surprise at being included on the bench for the World Cup opener against Japan.

The retiring Stephen Larkham starts for the Wallabies but the long-term search for his replacement seems to have taken a turn with his selection.

"I really didn't think it would happen so soon. I'm being thrown into the deep end but that's good for me," Barnes said. "I didn't think it'd get to this level so soon but it's a bonus and I'm just really excited."

Barnes had been told to rest and that he would not be needed for the World Cup after injuring his groin, but the player who impressed for Queensland in the Super 14 believes that being let-down allowed him to recover in his own time and not risk exaggerating the strain.

"I was told by the doctor last week that I wasn't going to be selected but I think it was a smart play from the doc," the former League player claimed.

"I would've been running around like a Staffy [Staffordshire] dog if I'd been told that I was a chance at playing so I think the doc did me a favour there."

Barnes had been told that his only role would be to look after the team mascot, a stuffed Wallaby.

RM / Eurosport