Pacquiao is clearly past his chin prime

Maybe past prime with all the wars he's been in. But the simple explanation could be that he just got hit by the perfect counterpunch.

 

Its not the same either that or JMM just become a much stronger puncher at age 39 which is unlikely, the second shot was so perfect that it probably would have koed Pac at any stage of his career but the first shot is the kind of shot that we are accustom to see Pac take once in a while without much bother and this time he fell like a dummy, its clear that all those wars are finally catching up to him you can hit a house many times until it gets to the point where the roof falls it looks the roof has finally fell on Pacquiao.