I'm not talking about current benchmarks, but theoretical speed. As a language (not an implementation, set of libraries, etc.) Rust will allow for programs to run as fast as C or C++ in all situations.* Ada, Scala, Go and Haskell may be able to do better in isolated situations, but in general this is not true for them. A lot of the time, this doesn't matter, but it's very important when you want to be considered a serious competitor in the domain of systems languages.

* Pending some in-the-works reforms, and not including implementation-specific features like labels as values (https://gcc.gnu.org/onlinedocs/gcc-2.95.3/gcc_4.html#SEC64).