Teleportation is not the same thing as raw speed. In raw speed, Goku is much much faster than Mewtwo. If you'd like to dispute that claim I can link you about a half dozen things that prove very weak versions of Goku were faster than light, meaning with less than 1% of his power he can circle the Earth several times in 1 second.
Concerning teleportation, I don't believe Mewtwo has ever shown interstellar teleportation, while Goku has displayed not only interstellar teleportation, but even trans-dimensional teleportation across infinite distance. So unless proven otherwise, Goku's teleportation > Mewtwo's.
With Goku's telepathic resistance, and his extremely retarded durability, I don't see how he's gonna be able to hurt Goku. Also, I'm assuming this is movie Mewtwo? Well, in the movie Mewtwo had to focus on things to attack them. When Goku sees him gearing up for an attack, he's not just gonna stand there, he's gonna vanish, because he can move far faster than Mewtwo can keep up with.