Computer blitzed nine second game (5,6)
I believe the answer is:
table tennis
'game' is the definition.
(table tennis is a kind of game)
'computer blitzed nine second' is the wordplay.
'computer' becomes 'tablet'.
'blitzed' indicates anagramming the letters.
'second' becomes 's' (common abbreviation).
'nine' anagrammed gives 'enni'.
'tablet'+'enni'+'s'='TABLE-TENNIS'
(Other definitions for table tennis that I've seen before include "Ping-pong" , "Ping pong" , "Indoor game" , "sport" .)