The whole Sasaki thing, my though:
Oda want to take out Sasaki from the race to find Yamato, Who´sWho already make it clear that Sasaki was his only rival in last chapter.
Oda want that Who´s Who clearly find Yamato no one else. So he need some cheat trick to take out Sasaki of the race, but he clearly didn´t want also that Sasaki get hurt/damaged because he wanna use him later in the story again.
Kyoshiro come in and catch him without doing any damage on him, clearly the surprise effect on Kyoshiro side while Sasaki don´t even know that Kyo betray the beast pirates. Overall Sasaki get captured by Kyo but without taking any damage, which means he come soon back. And now Who´s Who have his free way to win the race and find Yamato, Oda clearly want the battle with Who´s Who vs a Calamity.
As I said, everyone who face at this point Who´sWho gonna take the L(everyone who isn´t named Luffy,Zoro and Kid). After the Calamity the most important role get to Who´s Who and Oda clearly show it with the characterbuilding and the overall hype for him.