It could be just an excuse though. But good for him because he was able to win the fight, so regardless, that doesn't make him a bad fighter since Ngannou trained hard and wants to win also. Now, against Usyk, he can't say that he will be undertrained because this is a serious matter, it's an undisputed fight and everything is at stake here, including his popularity.
He was just lucky that the judges was in his favor on that fight. Everyone is saying that he will dominate and it will not go to distance. But there are boxing pundits who says that he almost lost that fight and it almost cost him a big payday against Usyk.
And so Francis Ngannou will have, I will say a second chance, this time it's better for him as Joshua doesn't have the chin and if that raw power of Francis touches that glass chin of Anthony, so it won't be a easy fight for him.
For Francis, he could be more familiar with boxing right now, and will be full of confidence based on his last performance against Tyson Fury.