Why did Holmes consider the bearded man to be clever ? Chapter 4

It is interesting that Holmes acknowledges his adversary's cleverness. For the story to be interesting, the pursued person (here, the man in the cab) must be a match for Holmes. Such a match of intellect is crucial not only for the reader - who wants an interesting story - but also for Holmes himself - who would likely be bored if he did not confront a mystery worthy of his genius.