WBA, WBC 'franchise' and WBO lightweight champion Vasiliy Lomachenko has responded to the verbal jabs by Teofimo Lopez, the IBF belt holder in the same division.
The pair are due to fight on October 17 at the MGM Grand in Las Vegas to unify the titles.
Lomachenko has engaged in something of a running war of words with Lopez in the build-up to the fight, but he has taken exception to Lopez’s claims that he could end the Ukrainian's career.
Speaking to Sky Sports, Lomachenko said "In my country, if you insult somebody, you'd better be prepared for them to hurt you.”
"If we were back in my country, he would learn pretty quickly that he can't run his mouth like that,” he continued.
"Whatever I say, I believe in it. So what he's saying, for example, he actually believes. But if he doesn't follow it up with actions and fulfill those words, then he chose those words poorly to begin with. I'm definitely not going to feel sorry for him."
The 32-year-old boxer last fought at the end of August 2019 when he defeated Luke Campbell by unanimous decision, but he is not worried by the extended break away from competitive boxing.
"Everything is good," Lomachenko claimed.
"I've had a one-year break without a fight. Now I'm healthy and happy. I'm 32, I've been very long in this sport so, of course, my body has tired a little bit. But I've had a break.”
He explained that he sees a bout with Lopez as a means to achieving his goal of unification.
"I am close to my goal. This is one step closer to my dream. Fans love the interesting fights with top fighters. Now we have a unification (fight) and we are the top fighters in this weight class. It was my goal when I started my pro career. It was always my dream. I did 126 lbs, I tried 130 lbs, now I try 135 lbs and it is very close. I want to unify.
"I want to put my name in boxing history. I started very early - my second fight of my pro career was a world title fight. I want to do something special with this opportunity."