False move of young girl upset teacher’s favourite, perhaps (7)

I believe the answer is:
misstep
'false move' is the definition.
(I've seen this before)
'young girl upset teacher's favourite perhaps' is the wordplay.
I cannot quite understand how this works, but
'girl' could be 'miss' (term of address for an unmarried woman) and 'miss' is located in the answer.
This explanation may well be incorrect...
'of' is the link.
Can you help me to learn more?
(Other definitions for misstep that I've seen before include "Badly judged move" , "False move" , "Error" , "Badly judged footing" , "bad move" .)
