Two matches into his Test career and rising Wallabies tighthead prop Tom Robertson isn’t yet sure if he belongs.

But he no longer feels like a fraud.

The well-spoken 22-year-old, who is finding the balance between studying a full-time medical degree with a burgeoning international rugby career, is on his first major tour as a Wallaby – and gaining invaluable experience at every turn.

A fortnight ago he was thrown into the fray by coach Michael Cheika, who gave the highly rated scrummager a stint off the bench against Argentina in Perth.

That was when his outlook on being a Wallaby changed forever.

“You just don’t feel like a fraud anymore when you call yourself a Wallaby,” Robertson said.

“You’d always say ‘I’m in the squad but I haven’t played yet’.

“That’s a pretty crap feeling and once you get your cap and you make your debut, you don’t sort of feel like a fraud saying you’re actually a Wallaby.

“It’s a good feeling but you always want to add more.”

Robertson, who also featured off the bench in last weekend’s tough loss to South Africa in Pretoria, is fighting to be in Cheika’s match-day 22 for Saturday’s final Rugby Championship Test against Argentina at Twickenham. But he faces a challenge from Allan Alaalatoa who has recovered from a knee injury.

For the rookie, who started the Super Rugby season on an emerging player contract but made such enormous strides his presence could no longer be ignored, it will be a special occasion.

Robertson had never been to Europe before this trip, let alone set foot inside Twickenham Stadium.

But the likes of Drew Mitchell and Adam Ashley-Cooper have given him an insight into what to expect.

“To come to one of Europe’s – or the world’s – best grounds it’s going to be a great feeling if I get out there,” he said.