Inconsistent authentication via Google account

When I login & create an account via Google I don’t know a password for the account on Bitbucket (email’s password is not accepted), hence I’m unable to e.g. clone repo-s etc. And there is no working method to explicitly setup a password for Bitbucket. E.g. if I go to Atlassian profile settings and try to change password it asks for the old one which is unknown yet!