Shoot up to number one! (3)
I believe the answer is:
top
'number one' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe you can see an association between them that I don't see?
'shoot up' is the wordplay.
'shoot' becomes 'pot' (I've seen this in other clues).
'up' says the letters should be written backwards (in down clue: letters go upwards).
'pot' back-to-front is 'TOP'.
'to' is the link.
Can you help me to learn more?
(Other definitions for top that I've seen before include "Apex; child's toy" , "Zenith" , "Pinnacle" , "Toy; garment" , "Summit, peak" .)