I think based on what's shown so far that :
> Luffy vs Kizaru 1st round : (Luffy isn't serious)
Old Rayleigh's feat with Gear 5th being occupied with Kizaru .
> Luffy vs Kizaru 2sd round : (Luffy's serious)
Prime Rayleigh's feat :
Prime Rayleigh claimed that he would have left Kizaru in dust and helped Straw hats , basically a 2 v 1 in his prime something Serious Gear 5th did this chapter .