Fury one it was a hell of a fight probably the highest level heavyweight fight I have seen in a very long time both guys were tested and overcame and Usyk came out on top.
Dubois 2 no question. Usyk almost lost Fury I. In the aftermath of Fury v Ngannou I and many people expected Usyk to embarass Fury.
Depends what you value. AJ 1 and Dubois 2 are obviously alternatives and I think you could make an argument for Fury 2 as well. But Fury 1 was probably his hardest fight and he overcame it and scored a KD in the process so that's the pick for me.
I thought Fury would beat him. Both times. And I had both fights very close. The best MAN won though. Bearing Fury in fight one and coming back from obvious discomfort and, yes, shock that he was being outboxed and out thought in spots was, in hindsight, an incredible performance. Both men brought the best out of each other, a repeating phenomenon. I'd say AJ from AJ/Usyk2 was the very best version of AJ I've seen and the Fury of Usyk/Fury 1 was perhaps amongst the best versions of Fury we have seen. I think Fury 'fights to the level' if not to his opponents level, but to the level the challenge requires. Lazy bugger that he is...
Best performance is AJ 1. He never seemed to be quite as in good shape moving forward. Best win is Fury 1 though, unified the belts and beat the best heavyweight in the world (well, second best).
AJ2 can be contextualised by the war in Ukraine which as crazy at the time. That said his big wins do have different characteristics AJ 1: element of surprise in a masterclass Fury 1: came back from almost certain loss to practically stop fury Dubois 2: demolition job
Personally I think it's a toss up between AJ2, Fury 1 and Dubois 2 - they all have a case. The reason I cite AJ2 is that Usyk did not have the mid-rounds dip he had in the first, and IMO it's easily the best most focussed Joshua that we've ever seen in the ring, AJ improved just about every aspect of his game in that fight and executed as good as he could - but Usyk still nullified everything and had his way and IMO it was wider on round by round basis than the 1st fight. I think that's a big reason for Johsua's meltodown at the end because he KNEW it was as good as he could probably ever be and it still wasn't nearly enough. Dubois 2 was just ruthless, and Fury 1 showed how deep into his bad of tricks he can reach and adpat & find a way when it looked like things weren't going for him for a few rounds like had rarely happened before
Joshua 1 because Usyk was actually the underdog especially after the his performance vs Chisora which wasn't overly impressive. Usyk schooled Joshua and won a very wide UD. Dubois 2 because its a rare early stoppage for Usyk against a notable opponent dangerous opponent. Fury 1 for the heart Usyk showed and being able to adapt when he was losing. And it was the biggest fight for Usyk at Heavyweight deciding who was the best Heavyweight was. Those 3 fights are head shoulders above the rest and its down to your criteria on what one you pick.