Piece of magic that's celebrated by one on pitch (3,5)
I believe the answer is:
hat trick
I believe this clue is a double definition.
'piece of magic' is the first definition.
(e.g. taking rabbit out of a hat)
'celebrated by one on pitch' is the second definition.
(three goals in soccer or three wickets in a row)
'that's' acts as a link.
(Other definitions for hat trick that I've seen before include "instantly dispatching several?" , "Three consecutive successes" , "Three scored in a row as in soccer match" , "Taking three wickets with consecutive balls" , "Three wins in a row" .)