The British fighter will take on compatriot Daniel Dubois for the IBF belt at Wembley Stadium on Saturday (21.09.24) and says he has toiled to get back in title contention after suffering back-to-back defeats to Oleksandr Usyk in 2021 and 2022.
Joshua told BBC Sport: "I've worked hard and been through a lot of pain, and I've worked hard to get better.
"Hopefully those experiences won't happen again because as you saw that night, I don't like losing."
Joshua has won four fights in a row since his rematch loss to Usyk two years ago and claims that his skills in the ring have reached a "supreme level" in recent contests.
The boxer said: "I think I'm gifted with an ability to fight and compete. In boxing you're able to read certain tendencies, you're able to read your opponent, so I can always have an eye for that.
"But there's a supreme level that you can take it to. And it's happened over the past eight or 10 months. I've really honed in on those skills."
Joshua is the favourite to beat Dubois and become champion again but he is refusing to overlook the challenge posed by his "brilliant" rival.
He said: "He is a good fighter, a brilliant fighter. Everyone speaks highly of him. I think they underestimate me as well, so I will go out there and prove how good I am."