diff --git a/litellm/llms/aiohttp_openai/chat/transformation.py b/litellm/llms/aiohttp_openai/chat/transformation.py
index 0aaac824d72..b82c10eb1c1 100644
--- a/litellm/llms/aiohttp_openai/chat/transformation.py
+++ b/litellm/llms/aiohttp_openai/chat/transformation.py
@@ -83,5 +83,5 @@ class AiohttpOpenAIChatConfig(OpenAILikeChatConfig):
         model_response.object = _json_response.get("object")
         model_response.system_fingerprint = _json_response.get("system_fingerprint")
         if "service_tier" in _json_response:
-            model_response.service_tier = _json_response.get("service_tier")  # rebind-ok: fills the caller's response
+            setattr(model_response, "service_tier", _json_response.get("service_tier"))  # noqa: B010  # pydantic extra, not a declared field
         return model_response