diff --git a/fastapi_cache/decorator.py b/fastapi_cache/decorator.py
index 150afcd..d24c565 100644
--- a/fastapi_cache/decorator.py
+++ b/fastapi_cache/decorator.py
@@ -62,13 +62,24 @@ def cache(
             nonlocal coder
             nonlocal expire
             nonlocal key_builder
+
+            async def ensure_async_func(*args, **kwargs):
+                """Run cached sync functions in thread pool just like FastAPI."""
+                if inspect.iscoroutinefunction(func):
+                    # async, return as is
+                    return func(*args, **kwargs)
+                else:
+                    # sync, wrap in thread and return async
+                    return run_in_threadpool(func, *args, **kwargs)
+
+
             copy_kwargs = kwargs.copy()
             request = copy_kwargs.pop("request", None)
             response = copy_kwargs.pop("response", None)
             if (
                 request and request.headers.get("Cache-Control") == "no-store"
             ) or not FastAPICache.get_enable():
-                return await func(*args, **kwargs)
+                return await ensure_async_func(*args, **kwargs)
 
             coder = coder or FastAPICache.get_coder()
             expire = expire or FastAPICache.get_expire()
@@ -82,12 +93,13 @@ def cache(
             if not request:
                 if ret is not None:
                     return coder.decode(ret)
-                ret = await func(*args, **kwargs)
+                ret = await ensure_async_func(*args, **kwargs)
                 await backend.set(cache_key, coder.encode(ret), expire or FastAPICache.get_expire())
                 return ret
 
             if request.method != "GET":
-                return await func(request, *args, **kwargs)
+                return await ensure_async_func(request, *args, **kwargs)
+
             if_none_match = request.headers.get("if-none-match")
             if ret is not None:
                 if response:
@@ -102,10 +114,8 @@ def cache(
                 kwargs.pop("request")
             if not response_param:
                 kwargs.pop("response")
-            if inspect.iscoroutinefunction(func):
-                ret = await func(*args, **kwargs)
-            else:
-                ret = await run_in_threadpool(func, *args, **kwargs)
+
+            ret = await ensure_async_func(*args, **kwargs)
 
             await backend.set(cache_key, coder.encode(ret), expire or FastAPICache.get_expire())
             return ret