diff --git a/aiogram/fsm/storage/pymongo.py b/aiogram/fsm/storage/pymongo.py
index 5b891679..d547bb2f 100644
--- a/aiogram/fsm/storage/pymongo.py
+++ b/aiogram/fsm/storage/pymongo.py
@@ -123,23 +123,14 @@ class PyMongoStorage(BaseStorage):
 
     async def update_data(self, key: StorageKey, data: Mapping[str, Any]) -> Dict[str, Any]:
         document_id = self._key_builder.build(key)
-        update_result = {}
-        if not data:
-            update_result = await self._collection.find_one_and_update(
-                filter={"_id": document_id},
-                update={"$unset": {"data": 1}},
-                upsert=True,
-                return_document=True,
-                projection={"_id": 0},
-            )
-        else:
-            update_result = await self._collection.find_one_and_update(
-                filter={"_id": document_id},
-                update={"$set": {"data": data}},
-                upsert=True,
-                return_document=True,
-                projection={"_id": 0},
-            )
+        update_with = {f"data.{key}": value for key, value in data.items()}
+        update_result = await self._collection.find_one_and_update(
+            filter={"_id": document_id},
+            update={"$set": update_with},
+            upsert=True,
+            return_document=True,
+            projection={"_id": 0},
+        )
         if not update_result:
             await self._collection.delete_one({"_id": document_id})
         return update_result.get("data", {})