My my the 3 Chinese ladies in the 20km walk were gorgeous with shimmering abs in the sun! They did these girls dirty this time by making them race after the men, when the temperature had risen significantly. I personally would have put it off to the next early morning.
In any case, Yang Jiayu opened up a massive lead at the 5km mark, which is not normal. I didn't like it because it reminded me of the last (or prior) Olympics when a bald Chinese dude opened up too early and ended up losing steam, falling behind. She didn't though and all was well... until the 15km mark when Perez of Spain began to chase. The difference was 38 seconds. By 16km, she was only 30 seconds behind. By 17km, she was 20 seconds behind and it's looking dangerous for Yang. By 18km, that narrowed to just 15 seconds, but by 19km, it opened up back to 17 seconds. In the last kilometer, it became obvious that Yang wasn't getting tired and run down; the Spaniard was overheating trying to catch a Yang who was walking at equilibrium and had not began to sprint yet. Perez also accumulated 2 red cards for running attempting to chase Yang while Yang had none; so Perez had to be careful because 3 cards and she gets docked 2 minutes, won't win a medal. Yang's last KM sprint opened up the gap to 25 seconds at the finish line.
But the difference in endurance was even more obvious afterwards as Yang walked straight past the finish into the Chinese flag and began to celebrate and take pics. 25 seconds later, Perez passed the finish and immediately had to hold onto the walls to prevent collapse. Her team quickly came to her, draping a cold towel over her and holding her up. Yang had so much more left in the tank than Perez, the situation was always under control despite the temprary scare.