Nonsense. WB couldn't do it, while being enraged. And before you say he was injured, he completely ignored every damage he took, once he saw Ace die. Even when part of his head was blown away, he didn't even flinch. Before that, he was struggling to just stand.
Garp ain't beatin a fresh Akainu.
And the damage Akainu took from WB wasn't that great. Akainu didn't show any sign of being badly hurt or anything.