diff --git a/player/lua/defaults.lua b/player/lua/defaults.lua
index dcbb4e0f62..e0914115f5 100644
--- a/player/lua/defaults.lua
+++ b/player/lua/defaults.lua
@@ -615,6 +615,7 @@ local async_next_id = 1
 function mp.command_native_async(node, cb)
     local id = async_next_id
     async_next_id = async_next_id + 1
+    cb = cb or function() end
     local res, err = mp.raw_command_native_async(id, node)
     if not res then
         mp.add_timeout(0, function() cb(false, nil, err) end)