Paul Nasari knew he had a good fighter in George Kambosos Jr.

Nasari said that George had his first professional fight on one of his cards, and then he won his titles.

Nasari was correct.

Nasari says he sold out every time Kambosos fought at the Punchbowl Croatian Club when he won the lightweight title.

Kambosos is going to have many more watching. On Sunday, he will fight for the undisputed lightweight title at the Marvel Stadium. There will be 50 times that number.

Kambosos humble beginnings remain at the forefront of the champion's mind just days out from what is arguably the biggest fight in Australian boxing history. He says that a chip on the shoulder continues to drive him.

Kambosos said he was never fed like the other guys and that he wasn't given a platform straight away.

I look at myself in the mirror and I think, "You know what, you got here the hard way." I would have said "You did it the hard way" if I had not gotten through the Lopez fight. I never cheated myself.

It is so important that I go through the grassroots, going through the way we did it, selling the tickets, hustling every bit that I could, building my fan base, a lot of people were turned off by me at the start but I got their attention. If they are still not supporting me, they are watching me. I wouldn't have it any other way because every bit of my career has been the way it was meant to be for me.

George Kambosos Jr. is at last preparing to fight on home soil having worked his way to the lightweight titles overseas Brendon Thorne/Getty Images

Nasari remembers the fights when he knew Kambosos was special.

He took apart Michael Correa for the title. He jumped out of the ring after hitting Correa with a left hook. In the middle rounds, when he hurt him, he just took his time and it was like he wanted to go the distance. He won by unanimous decision.

Kambosos said that the fight was just another example of proving the doubters wrong.

He was a former two-time Australian champion and he had an Australian title when he fought me. I battered and bruised him over 10 rounds and showed Australia and the local boxing community that I was who I was when I got that belt off him. Who is this young kid? Who is this guy who is talking too much? Does he have it?

I showed on that day that I had it, and that I would be world champion one day.

The rise of junior middleweight Tim Tszyu, the rise of IBF women's bantamweight world champion Ebanie Bridges, and the growing list of Australian heavyweights are some of the things that are happening.

The sport can get ahead of itself with young fighters who enjoy success on home soil before getting found out on the world stage.

Kambosos is different from Tsyzu because he stayed in Australia. The lightweight champion headed offshore in the search for sterner training opponents and eventually the fights that would put him within reach of a world title showdown.

He spent a lot of time over in America training and sparring, and that definitely helped him, according to Australian boxing analyst Paul Upham. People underestimate how hard it is to go and fight overseas, to fight away from your country, according to Hall of Fame Australian boxer Kostya Tsyzu. People don't realize how hard it is.

George Kambosos Jr works out in his Ferocious Gym in Mortdale, Sydney, Australia, April 21, 2022 Brendon Thorne/Getty Images

Australian boxers only spar local guys, and unless they bring quality opponents in from overseas, they only have a certain level of talent.

Kambosos was given little chance of dethroning Lopez again back at the New York City arena in November last year, despite wins over Mickey Bey and Selby. The story of Kambosos' career so far is that he outboxed Lopez, overcoming a late knockdown to claim each of the lightweight titles.

Kambosos has the ability to counter whatever Haney throws at him on Sunday, because of the victory and the adversity that he faced within it.

I knew I was going to be world champion and I had that inside of me that I would win that fight. I showed what a warrior I am. I can show it, bits and pieces, and I am a warrior and a Spartan. I got up and fought back in the 11th and 12th rounds, so many guys would have said that was enough for tonight.

The comforts of fighting on home soil, which Kambosos hasn't experienced in since 2017, are a huge advantage for the Australian. Fans expecting to see a homecoming for Kambosos should not get ahead of themselves, as Upham warns, because he is wary of Haney's history.

He said that Haney was an out-and-out boxer with a good amateur record. He had his first few fights in Mexico when he was 17 years old, because he couldn't turn pro in America until he was 18. The guy is very skillful and he is a genuine talent. He is not a knockout puncher, but he is a very skilled and slick boxer. I don't know how that will affect him, because he won't have his father in his corner.

It is a real fight. Haney is considered the favorite by most people overseas. They think that Lopez was handicapped because of his weight issues and he had a lot of drama with his family. They think that George beat a weakened guy because Lopez wasn't the best that night.

Kambosos has a chip on his shoulder.

George Kambosos Jr [L] defeated Teofimo Lopez by split decision at Madison Square Garden, New York City, November 27, 2021 Rich Graessle/Icon Sportswire via Getty Images

Kambosos has been able to train at home, spend more time with his family, and finally put on a big show for the Australian sporting community, but he still can't shake the thought that he will never be able to fulfill his promise.

He says that is a good thing.

The chip on my shoulder makes me hungry. They are going to watch the ones that have said things about us. I bet you won't find them on the fight night because they have nothing to do with us or this show.

I don't think it will ever go away, but maybe when it does, I will give it in and move on.

After honing his craft on the other side of the world, and answering all of his critics, moving on is still on the agenda. To be crowned the undisputed lightweight champion of the world, you have to defeat Haney on Sunday.

Kambosos will have a special place in Australian sporting history.