In story an setting it is the themes that are used that defines a genre. Not objects.
The thematic aspects of Star Wars, such as the force, black and white good versus evil views, knights using swords, and so forth have a very strong fantasy aspects. Take away the Force (the magic system of the setting, the Jedi Order (a holy order of Paladins), and the such you wouldn't have Star Wars.
keep the themeatic aspect of Star Wars, but place it on an ocean world with medieval style weaponry you would still have the same story of a young lad becoming a knight, and redeeming his father and killing the despot. The starships and blasters are only window dressing.