A knight’s empty armour rides to his rescue when enemies attack him during his bathing in a river

Many years ago I once watched a rather mediocre film with a single spectacular scene in which – if I remember correctly – a knight takes a bath in a river or lake in a forest. Then, enemies notice him and want to attack him, but his empty armour (magically) comes to life to save him, riding on his horse and killing the (two?) men with his sword.
The most spectacular part is the horse and empty armour (riding it), running at full speed through the shallow river, to rescue the knight. I remember the horse running towards the observer/camera, while water splashes everywhere. Very impressive for an otherwise cheap and unattractive production.

I hope to see this scene once more. Curious to find out if it really was as good as I remember. The story line described above should be specific enough; just hope that someone has seen it and remembers. Thanks in advance.