Advantage in competition from loaf, singular baked item (4,5)
I believe the answer is:
head start
'advantage in competition' is the definition.
'head start' can be an answer for 'advantage' (head start is a kind of advantage). I am not certain of the 'in competition' bit.
'loaf singular baked item' is the wordplay.
'loaf' becomes 'head' (slang term).
'singular baked item' becomes 'start' (I am not sure about this - if you are sure you should believe this answer much more).
'head'+'start'='HEAD START'
'from' acts as a link.
Can you help me to learn more?
(Other definitions for head start that I've seen before include "Boost?" , "It improves the chances of success!" , "Substantial initial advantage" , "A good beginning using one's loaf" , "advantage, initially" .)