diff --git a/src/guidellm/backend/openai.py b/src/guidellm/backend/openai.py
index e62e9003..680578cc 100644
--- a/src/guidellm/backend/openai.py
+++ b/src/guidellm/backend/openai.py
@@ -688,7 +688,7 @@ def _extract_completions_delta_content(
             return data["choices"][0]["text"]
 
         if type_ == "chat_completions":
-            return data["choices"][0]["delta"]["content"]
+            return data.get("choices", [{}])[0].get("delta", {}).get("content")
 
         raise ValueError(f"Unsupported type: {type_}")