Tournament seed produces cracking spell (4,6)
I believe the answer is:
open sesame
'cracking spell' is the definition.
The answer and definition can be both related to communication as well as being singular nouns.
Perhaps you can see a link between them that I don't see?
'tournament seed' is the wordplay.
'tournament' becomes 'open' (open is a kind of tournament).
'seed' becomes 'sesame' (sesame seed is a kind of seed).
'open'+'sesame'='OPEN SESAME'
'produces' is the link.
Can you help me to learn more?
(Other definitions for open sesame that I've seen before include "free entry" , "Words of Ali Baba" , "Spell from Ali Baba and the Forty Thieves" , "Magic password" , "spelling words?" .)