The 32-year-old actress takes on the role of Major Motoko Kusanagi in the live-action adaptation of the hugely popular Japanese anime series, and the 46-year-old filmmaker was amazed by how well the flame-haired beauty subtly acted out the droid's realisation of their human qualities.
British-born Sanders said he feels ''so lucky'' to have gotten the chance to work with the in-demand Hollywood star.
Speaking to the latest issue of NME magazine about working with the 'Lucy' star, he said: ''At first, the human mind and the machine body was more encapsulated by the machine.
''As the film develops, though, and as she understands more about who she is as a human, she starts to become a bit more human.
''It's a hard one. Scarlett joked a lot about it.
''She said, 'You've taken away everything that an actor relies on to create a character!
''But she did on amazing job of finding the nuance and subtlety of the humanity awakening within a robot.
''It was a very hard performance but she's an incredible talent. I was so lucky to get the chance to work with her on this.''
Sanders also praised Scarlett for being an example of how to beat the Hollywood gender wage gap as she is at the top of her game starring in a masculine movie and bringing a female touch to it while earning an equal salary to her male counterparts.
He explained: ''That's definitely part of it. Everyone talks about the glass ceiling for wages for women. But when I think of Scarlett, she's standing on the roof of that building [as the Major] and she's also standing on the roof of that glass ceiling as a woman saying, 'I'm up here. I'm leading a franchise. I'm doing everything a man can do. I am getting paid the same as a man and I'm going to kick ass the same as a man!'
''What 's also brave is that the film has a femininity to it.
''It's very emotional but it's also got a very hard masculine edge of violence and action to it.
''And Scarlett is equally at home with both.
''I think that's why this film is different and why it's original.''
It's time for a riot grrrl revolution.
How are the world's biggest superstars changing?
Who inspired Royse?
Graham J tells all about his experience with the Jazz Journal.
An interview with Nick Wilson.