Sean McMahon has warned his detractors and positional rivals that he won’t be giving up the Wallabies No.8 jersey without a fight.

Coach Michael Cheika has endorsed the abrasive McMahon as the clear frontrunner to replace David Pocock, who will take a break from rugby in 2017, at the back of the Australian scrum.

With Pocock out injured again, he gets another chance to prove his worth in Saturday’s Rugby Championship clash against South Africa in Pretoria.

The 22-year-old has heard all the talk before – that he’s too short to play at No.6, too small to be an effective No.8, and unlikely to unseat Michael Hooper anytime soon at No.7.

But that won’t deter McMahon, who has vowed to make the position suit him, even if he doesn’t traditionally suit the position.

“Any opportunity to throw on the gold is an opportunity and if eight’s going to be that opportunity, I’m going to be taking it with both hands,” McMahon said.

“There’s players like Lopeti Timani and that who could easily lock that role down or take it from me but I can tell you it’s not going to come easily – they’re going to have to work for it.

“Learning from a player like Pocock, who is also a seven who’s worked his way into eight, I think he’s proved that if you’re capable (you can) go into that eight role and really make it your own.

“I might not be the tallest player out there, but I’m going to (counter) that with speed.

“I’ll just continue to bring that where I haven’t got the height.”

McMahon has had his tattooed left arm covered up during training this week after some recent new ink on his elbow – a third eye, which he admits doesn’t hold any special meaning.

“There’s a few things on here that don’t really mean much, we’re just filling her up at the moment,” he said.

But further up his arm, there’s something that does hold significance – a quote he had etched as an 18-year-old that sums up his approach to rugby, and the reason why Cheika is such an unabashed fan of his.

“‘Life is what we make of it.’ If you’re not willing to have a crack and have a dig, you’re not going to get anywhere,” McMahon said.

“It’s probably what I take into rugby. If I’m not going to be out there having a crack, what’s the point in playing?”