If Berrick Barnes were English rather than Australian, the chances are that instead of lining up in a World Cup quarter-final this afternoon he would be preparing for a match in the Guinness Premiership. The 21-year-old outhalf was regarded as a wildcard selection in the Wallaby squad, having played only 22 matches for the Queensland Reds since switching codes two years ago, but such was the assurance he showed in his first Test start, against Wales last month, that he gave the impression of being a seasoned international.

Barnes was not picked as a first choice and has received his opportunity only because of the knee injury to the veteran Stephen Larkham, but Australia have resisted any temptation to shield the tyro and move Matt Giteau to number 10 in Marseille today. "Berrick showed in Cardiff that he was perfect for this," said the Wallabies' skills coach, Scott Johnson.

"Some guys are worriers, some are more controlled. Some want clear messages. Others don't. Berrick is different, because he simply feels he is up to it. Our task this week has to be to keep him calm."

Barnes was at school when Australia lost the 2003 World Cup final to England in Sydney. He watched the match at his granny's house and was so impressed by Jonny Wilkinson, that in the following months he bought a book written by his opposite number today, as well as a DVD.

"I enjoy all that sort of thing. It's not like I get intrigued by the rugby stuff, so to speak, I just like learning about people and how they go about things. It's the mental side I like to get into. Getting your head on and right is the key to this game. Do that and pretty much everything else takes care of itself."

Barnes was chosen for the World Cup despite a Super 14 campaign in which the Reds struggled and he was forced to curb his instincts and nurture a weak pack. The Australia management recognised his potential and brought him in.

"I did not expect to be here, let alone start a quarter-final," said Barnes. "It's a bit of a dream: it is the sort of game you used to imagine as a kid playing in the back yard with a plastic set of posts. I have not changed the way I play and I will not."

Barnes, who is from Kingaroy, said: "I get nervous, but I've a wealth of experience around me in George Gregan, Matt Giteau, Stirling Mortlock and Chris Latham.

"You can only be excited by an experience like this. Matches between Australia and England are always about the passion to win. I'll be keyed up for it."

Barnes followed rugby league as a boy and made his debut for Brisbane Broncos when he was 18 but after nine matches he signed for the Reds. He had relished the prospect of facing England centre Andy Farrell, who misses the match due to a calf injury, having followed his league career.

"It would have been massive for me. When I think about coming up against players like Wilkinson and Farrell, it is hard to believe what is going on."

Having watched Wilkinson destroy Australia's party four years ago, Barnes has been practising his drop-goals this week. Should he land a winning one this afternoon, it would be Kingaroy of the Rovers stuff.