Martinez continued to take big shots after the KD and didn't fall. i think his chin is solid considering Chavez had to have weighed at least 180.
A 180+lb fighter was fighting scared and getting hurt by a 165lb fighters jab. Chavez's weak manidble will be exposed with a year.
Chavez's chin is overrated. He covered up quite a bit, and obviously can take a great punch but he's not his father when it comes to durability. You have to go through the fire and take chances. To me, he suspect he could have been knocked out had he tried to punch in between the punches. Perhaps that's an issue of mentality, more so than chin. Martinez backed him up good at points, though.
martinez chin is well tested.. who has chavez jr faced that has punching power to knock him out, who has jr. faced that is known for his knockout power all over boxing :hat