diff --git a/src/fastmcp/client/client.py b/src/fastmcp/client/client.py
index 1fee12ff7..03fb7fd5a 100644
--- a/src/fastmcp/client/client.py
+++ b/src/fastmcp/client/client.py
@@ -268,6 +268,8 @@ class Client(Generic[ClientTransportT]):
 
     async def close(self):
         await self.transport.close()
+        self._session = None
+        self._initialize_result = None
 
     # --- MCP Client Methods ---
 
diff --git a/tests/client/test_stdio.py b/tests/client/test_stdio.py
index 55d430f7c..71bbefe4a 100644
--- a/tests/client/test_stdio.py
+++ b/tests/client/test_stdio.py
@@ -121,9 +121,7 @@ class TestKeepAlive:
         client = Client(transport=PythonStdioTransport(script_path=stdio_script))
         assert client.transport.keep_alive is True
 
-        with pytest.raises(
-            RuntimeError, match="Server session was closed unexpectedly"
-        ):
-            async with client:
-                await client.close()
+        async with client:
+            await client.close()
+            with pytest.raises(RuntimeError, match="Client is not connected"):
                 await client.call_tool("pid")