You can do something clever in any language. There are plenty of really, really smart people that spend a lot of time writing incomprehensible (to me) Haskell that outperforms C.
The question is, do you have to do something clever to get performant code in the language of your choice?
In Julia -- not often. I've written around 50kloc of Julia; almost all of it is first-pass prototype code that manages to be performant despite itself. The most polished code I've written in Julia is about 100x faster than the MATLAB it replaced.
IMO, the main advantage of Python is its massive library of modules. As a prototyping language, on the other hand, it just seems to me that Julia is more flexible.