High-flier, possibly, producing superior performance on course (6)

I believe the answer is:
birdie
'performance on course' is the definition.
The definition and answer can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?
'high-flier possibly producing superior' is the wordplay.
I cannot really understand how this works, but
'flier' could be 'bird' (synonyms) and 'bird' is found within the answer.
The remaining letters 'ie' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for birdie that I've seen before include "One under in 20 across" , "One watched" , "Good hole" , "low score" , "One under par - watch it!" .)
