Was panting, having rushed for half the game (6)
I believe the answer is:
gasped
'was panting' is the definition.
I can't judge whether this defines the answer.
'rushed for half the game' is the wordplay.
'rushed' becomes 'sped' ('speed' can be a synonym of 'rush').
'for' means one lot of letters go next to another (I've seen this in other clues).
'half the' indicates taking half.
'game' with half the letters taken is 'ga'.
'sped' put after 'ga' is 'GASPED'.
'having' acts as a link.
Can you help me to learn more?
(Other definitions for gasped that I've seen before include "Struggled for breath" , "Took a sharp breath" , "Breathed laboriously" , "Drew in breath sharply, as in surprise" , "Drew breath in sharply as in astonishment" .)