let down

[navi]

1) My favorite team let me down this weekend. They lost four-nil.
2) My favorite team disappointed me this weekend. They lost four-nil.

I think 'let down' is usually used when something has been promised, and yet I find '1' correct. I think '2' is correct too, but sounds less natural to me.

Are they both correct?
Do they mean exactly the same?

Gratefully,
Navi

[Erik_Kowal]

General expectations can be let down as well. It's not just failures to keep promises that can lead to let-downs.

Both versions sound fine to me; 1) is more colloquial. No discernible difference in meaning unless the speaker of 1) actually lost money, or a bet, as a result of the losing score.