^^^^^^^^^^Rayleigh >>>> Sengoku
He was with Pirate King ruling the Oceans ..
I doubt they made him FA because of power...Sengoku is wiser and that made him a suitable candidate and Garp>Sengoku so by you saying FA is strongest and Garp being a VA is stronger than Sengoku then are you saying FA>VA>AI personally think sengoku should be able to win as he was fleet admiral which is stronger then regular admirals .....
He was loosing the fight......I'd say rayleigh. We've seen rayleigh duel an admiral with moderate ease already. Imagine prime rayleighs power. Besides, I think the rayleigh-Roger power relationship would have been something similar to luffy - zoro.