Of the billion dollar OS movies (Titanic, Avatar, F7, F8, TFA, and JW), Infinity War has already captured 1st place in the following markets:
India
Indonesia
Philippines
Thailand
It is getting extremely close in the following countries, and should pass the record holder no later than this weekend:
Malaysia
Mexico
Singapore
It may have a lot more smaller territories, but I haven't seen confirmed numbers for places like Vietnam yet.