Worst place - and best - for a brief rest (3,4)
I believe the answer is:
pit stop
'best for a brief rest' is the definition.
I know nothing about this answer so I cannot judge whether it can be defined by this definition.
'worst place' is the wordplay.
'worst' becomes 'pits' (I've seen this in another clue).
'place' becomes 'top' (top is a kind of place).
'pits'+'top'='PIT STOP'
'and' is the link.
Can you help me to learn more?
(Other definitions for pit stop that I've seen before include "Break for refuelling" , "for rest of travellers" , "F1 race feature" , "Break for fuel etc." , "Pause for refuelling etc during race" .)