Board Thread:Versus Debates/@comment-34656247-20180726110937/@comment-1751565-20180728140933

FUN FACT: In Boruto, just before he hits the Uber White Zetsu, Konohamaru himself stated The Third aka The Professor could use Rasengan as well....and since he is in his prime..

Honestly I say Hiruzen wins. Power isn't everything and although Bee is undoubtedly very powerful, its not like he is undefeatable. Hiruzen is way smarter and has more knowledge etc plus has a variety of Sealing jutsu, and other ninjutsu skills. It will be close only if B enters Bijuu Mode.