But despite having stood toe-to-toe with the Springbok giants, Welsh coaches sent the Newport-Gwent Dragons second-row down the gym to bulk up, resulting in Charteris moving from 110kg to 130kg.

His new found muscle helped propel him into Warren Gatland’s starting XV for all four autumn internationals last year; the first time the 26-year-old has found himself as a Test regular in his career.

But since the autumn injury has limited Charteris to just a handful of games for the Dragons and he admits he has it all to do to regain his starting position in time for the Six Nations.

He said: “After the autumn internationals we all had individual feedback so we know what we have to do between now and February.

“That campaign is over and a new one is about to begin. I am effectively back to square one so I have got to do everything I can before February 6.

“It is at the back of everyone’s minds that we have a month to get that Test jersey.

“I had four games on the bounce in the autumn and that’s the most I have ever had. Mostly I have been used off the bench but you need the games to get that consistency.

“The more you play, the more your confidence goes up and you know exactly what your coaches want from you.

“I am a very different player from when I made my debut. Going up from 110kg to 130kg is quite a big difference and I am now much better equipped for international rugby.

“I always needed to put weight on when I was 20/21. I was not as developed as I wanted to be so I knew I had to put on the pounds.

“I have naturally filled out as well but it has been difficult to get to my weight now. We tried lots of options but now I have a structured diet that I am happy with.

“The academy boys now are all so strong but they have to start from a lot younger. That’s the way the game is today.”

Charteris is not the only Dragon with international aspirations, with flanker Dan Lydiate also pushing hard, while the unfortunate Joe Bearman looks to be have been ruled out of the Six Nations with an abductor muscle injury.

Unfortunately Charteris and Bearman are a number of recent injury victims at Rodney Parade and that casualty rate has scuppered a promising start to the season.

But while the Dragons finished bottom of the pile among the Welsh region last year, Charteris is determined to restore bragging rights to the Men of Gwent.

He said: “It would be a huge achievement for us to finish as the top Welsh region.

“We were the bottom region last year and it would be nice to throw some banter back in certain people’s faces.

“It is important we do step up. We have been hurt by injuries: we lost our two scrum-halves and our two ball carriers but unlike other teams we can’t go out and buy a South African international to replace them.

“That’s just the way things are and we won’t feel sorry for ourselves. We have had a bad set of results recently so there is a huge month for the club and for myself.”