Saul 'Canelo' Alvarez has been in there with some of the best fighters of his generation.
Amir Khan, Gennady Golovkin and Billy Joe Saunders are just a few of those who have come off second-best against the Mexican.
But boxing's pound-for-pound king believes beating Dmitry Bivol will be his biggest challenge yet.
The duo go head-to-head for the WBA light heavyweight title this weekend on Saturday night at the T-Mobile Arena in Las Vegas.
And Canelo Alvarez knows it won't exactly be a walk in the park despite the odds.
Speaking to ESPN, he said: "He has a really good jab. He manages distance really well. He's a really good boxer.
"So it's going to be difficult, especially the first five rounds for me.
"But we've trained really good. We know how to get in there and throw my punches.
Canelo Alvarez is the pound-for-pound king in boxing
"We know. We trained for that. You always know in the first round.
"You get in there and try to see the speed, the power, the movements, what he does when you feint.
"So a lot of things go on in the first round and then you start doing your job."
Bivol, 31, believes Canelo has never faced anyone like him before and insisted he doesn't care about the odds before adding he is focused solely on the fight itself.
The Russian fighter told Matchroom Boxing's YouTube channel: "All my pro career I was the guy who should win the fight but now more people say Canelo should win.
"I understand why because he has a big fanbase and now this is a big challenge for me to prove myself to people.
"All people, all boxers, are different. We are all unique people with unique qualities. My set of qualities are unique too.
"I'm pretty sure all my opponents were different and me too of course.
"I will be something new for him and he will be something new for me too.
"I don't think about it. I think about only my fight. It doesn't matter about which plans he has or we have after the fight.
"For me, now, I only have one plan, and that is to fight on May 7."
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