diff --git a/authlib/integrations/httpx_client/oauth2_client.py b/authlib/integrations/httpx_client/oauth2_client.py
index 152b4a25..fd184483 100644
--- a/authlib/integrations/httpx_client/oauth2_client.py
+++ b/authlib/integrations/httpx_client/oauth2_client.py
@@ -104,6 +104,17 @@ async def stream(self, method, url, withhold_token=False, auth=USE_CLIENT_DEFAUL
             method, url, auth=auth, **kwargs) as resp:
             yield resp
 
+    def send(self, req, withhold_token=False, auth=USE_CLIENT_DEFAULT, **kwargs):
+        if not withhold_token and auth is USE_CLIENT_DEFAULT:
+            if not self.token:
+                raise MissingTokenError()
+
+            self.ensure_active_token(self.token)
+
+            auth = self.token_auth
+
+        return super(AsyncOAuth2Client, self).send(req, auth=auth, **kwargs)
+
     async def ensure_active_token(self, token):
         async with self._token_refresh_lock:
             if self.token.is_expired():