Usyk. Usyk expose Povetkin and Mike Tyson in that number for lack of good footwork against Klitschko, Lewis, Holyfield, etc. This is how you fight notorious clinchers. And this was 37.5 years old Usyk. Dont compare old and washed Usyk to past prime legends. Compare AJ 1 version(still not prime) or his CW version, as he was prime back then.
This is quite an interesting style matchup - Sasha had a vicious uppercut, and is not massively dissimilar in style to Briedis who pushed a prime Usyk the hardest. I'd say Usyk survives a couple of hairy moments to win a points decision though