Over the past four years, the year 10 Kaikorai Valley College pupil has made quite a name for himself on grappling and freestyle wrestling mats around the country.
While competing between the under-38kg 2011 and up to 53kg last year, Murdoch won six Otago titles, one Canterbury title, four South Island titles, one North Island title and four national titles.
Now the pint-sized combat/fighting sports fan is hoping to clean up in the boxing ring when he competes in the 52kg-and-under section at the South Island Novice Championships in Christchurch this weekend.
Murdoch said he loved everything about combat/fighting sports and he was excited about boxing after beginning training last year.
He said it would be a fun new challenge and while he planned on wrestling again this year, he hoped to box for about the next five years.
Murdoch believed he had a good work rate. His wrestling background had taught him to be mentally strong and would help him deal with the adrenaline of boxing.
He said he was proud of all his wrestling achievements, but in particular those when he was competing against bigger boys, which had happened a lot over the past few years.
His second placing in the 53kg section at the national championships last year was one of his proudest when he went up in weight to challenge himself after cleaning out the 47kg section at the North Island and South Island wrestling championships earlier that year.
The Olympic Boxing Club (OBC) member said his long-term goal was to follow his older brother Shem into mixed martial arts, which was his real passion, and have some kickboxing fights.
Murdoch joined the Olympic Fight Centre last year.
It is the base for the OBC and the Team Hammerhead MMA team.
He said boxing coaches Tony Maitland, Bryan Usher and Andy Gillies, and Team Hammerhead coach Matt Toa and brother Shem Murdoch had been big mentors for him, and he would not be where he was at now without the guidance of former coaches Aaron Walton, Caleb Steven and Blake Tomlinson whom he started training under at the Todd Group and Combat Sports School from about 7 years old.
Murdoch said he hoped to become a personal trainer or work in the sporting sector when he left school so he could incorporate his fighting goals around a job.
In his spare time Murdoch likes to play video games and he enjoys playing rugby at school, but not on Saturday mornings as he did not really have the time and ''it was too cold''.
Shem (20) said words could not express how proud he was of Kasib.
''I never put any pressure on him, but he just overcomes and passes every expectation,'' Shem said.
With a record of six wins and four losses, Shem has been competing in MMA for about three years, but he believes Kasib is a step above him in potential and had a big future ahead of him.
''He is doing things out here that most adults don't do and he is only 13,'' Shem said.
The South Island Novice Championships are for debutant boxers or those that have had five fights or fewer.
It is open to amateur boxers under 40 years old.
Depending on the size of each division a boxer may have up to four fights.
FAST LANE
Name: Kasib Murdoch
School: Kaikorai Valley College
Sport: Freestyle Wrestling
Achievements: 2011, New Zealand Grappling and Wrestling Association National Championships, under 38kg, 1st; 2012 New Zealand Grappling and Wrestling Association National Championships, 42kg, 1st; 2013 New Zealand Grappling and Wrestling Association National Championships, 42kg, 1st, 47kg 1st; 2014 New Zealand Grappling and Wrestling Association National Championships, 53kg, 2nd.
