anai loses to mid-level sheiks, he'd get bodied by a ZeRo prepared for the MU. Only way a player like Ranai or Abadango could beat ZeRo is via shock factor, not pure skill imo.
I can't imagine ZeRo coming into that match the more versed of the two, but yes you are right. I think that Nairo is the only player in the world that can beat ZeRo in a best of 5, but the list of people gets bigger when you bump down to best of 3. Anti had such a good start in losers and it was very evident that ZeRo had the pure endurance to go through everyone while he fell short. Unfortunately for Anti the next time he has to fight ZeRo he'll be significantly more prepared, kind of like how Dabuz/Mr R/Esam/everyone that isn't Nairo have done significantly worse against ZeRo than they did in their first encounter. This is why I'm convinced that his next bo3 loss will be to a Japanese player or otherwise someone not on his radar.
rankings in least improvement required to most improvement required
IMO top people to win a best of 5
Nairo
Mr R
top players to win a best of 3
Ranai
Abadongo
any of the high level Japanese players with uncommon characters in the international metagame (Umeki, Salena, Earth, 9B)
Esam, Dabuz
Ally, Vnnie
Anti