diff --git a/google/auth/transport/requests.py b/google/auth/transport/requests.py
index 68f67c59b..7b3b8db60 100644
--- a/google/auth/transport/requests.py
+++ b/google/auth/transport/requests.py
@@ -293,7 +293,7 @@ def proxy_manager_for(self, *args, **kwargs):
         return super(_MutualTlsOffloadAdapter, self).proxy_manager_for(*args, **kwargs)
 
 
-class AuthorizedSession(requests.Session, _BaseAuthorizedSession):
+class AuthorizedSession(requests.Session):
     """A Requests Session class with credentials.
 
     This class is used to perform requests to API endpoints that require
@@ -390,7 +390,7 @@ def __init__(
         default_host=None,
     ):
         super(AuthorizedSession, self).__init__()
-        _BaseAuthorizedSession.__init__(self, credentials)
+        self.credentials = credentials
         self._refresh_status_codes = refresh_status_codes
         self._max_refresh_attempts = max_refresh_attempts
         self._refresh_timeout = refresh_timeout