Malak is a no-name Jedi/no-name Sith. He was Revan's flunkie. Relatively featless. On the other hand, he seemed to be a pretty badass leader who overpowered Revan, Bastila, and some other guy on the Leviathan, managed to tap into the power of the Star Forge, and so on.
Logically, here's how I look at it.
Revan is pretty powerful, imho, and one step down = Malak. Malak, thusly, could do moderately well against Dooku.
Thank you.
That and, IIRC, he killed a couple of Jedi with the Force alone.