A lot of people were saying experience, but it's really not that, Punk have been in form on the big stage so many times, and even while losing he maintained his composure. Never on a stage as big as this but that's the case for Tokido too.
Dude just lost to Tokido 10-0 before EVO, he knew Tokido had his number. If anything, it's Tokido who choked in their top-16 game.
EVO experience is completely different than a major experience.
How many times had ChrisG choked at EVO but easily won every other major before finally winning an EVO? The EVO nerves are crazy man, it can get the best of players.
Plus this is SFV at Mandalay Bay with peak crowd and you have to carry the back of a whole country and decades worth of hopes and dreams on your shoulders. It's not an easy task whatsoever.