"How could you have done it?" vs "How did you manage to do it"

Question

Could you tell me if there is any difference in meaning between the question how could you have done it and how did you manage to do it? For example:

The match seemed impossible to pull off, but you did. How could you have done it?

The match seemed impossible to pull off, but you did. How did you manage to do it?

I asked a similar question about the use of how could have done something question in expressing critisism and was told that the question how could you have done it sounds like a genuine question. This in turn got me thinking what is the difference between the two.

Answer 1

To me, "How did you manage to do it?" is simple and understandable.
The question "How could you have done it?" doesn't make sense in context. It would fit better in this setting:
"You knew I didn't want you to go out with her! How could you have done that? How could you hurt me so?"

In a modified context like that of your original question, this might make sense:
"Unfortunately, you've lost the match. How could you have done it differently?"

Answer 2

There is no real difference between the two.

As a native speaker:

How could you have done it?

Sounds more rhetorical as if you are amazed by the fact the person made a match but do not necessarily want an actual answer.

How did you manage to do it?

Sounds more genuine and is clearer that you want an answer.