Luffy was not defeated with a single attack, you are living in a dream world, and the situation to talk about stamina is very ironic because kizaru fought with luffy in the offscreen part without attacking named , both of them did not attack, they just punched each other and luffy got tired because of his devil fruit while ,kizaru was out of breath because of nothing, luffy did not use everything and did not exert much effort until the last acoc attack.
Stop crying and accept canon