Well, without more information about Mario Racic's work in science fiction, it's difficult to point out the best ones. However, if he is a new author, he might be exploring unique concepts in the genre. His works could potentially deal with futuristic societies, advanced technologies like AI or space exploration. But again, this is all speculation without more details.
Since I'm not familiar with Mario Racic's science - fiction works directly, we can consider some general aspects of great science - fiction. If his works follow these trends, they could be good. Great science - fiction often challenges our ideas about humanity, society, and technology. It might introduce new worlds and concepts that make us think differently. Maybe Racic's works have elements like complex characters in a science - fiction setting, or unique takes on time travel or alien encounters. To really know, more research into his body of work is needed.
I'm not sure specifically which works Mario Racic has in science fiction. There could be a lot of emerging or relatively unknown authors. Maybe searching in specialized science - fiction databases or forums could help.