Too much sport on waves, with cup match coming up (7)
I believe the answer is:
surfeit
'too much' is the definition.
(a surfeit of something is too much of it)
'waves with cup match coming up' is the wordplay.
'waves' becomes 'surf' (surf can mean foam from waves).
'with' says to put letters next to each other.
'cup match' becomes 'tie'.
'coming up' says the letters should be written in reverse (in a down clue, letters go up).
'tie' written backwards gives 'eit'.
'surf'+'eit'='SURFEIT'
'sport on' is the link.
I am not very happy about this link. Some or all of it may belong to another bit of the clue.
Can you help me to learn more?
(Other definitions for surfeit that I've seen before include "Excess, glut" , "excessive amount" , "it's more than one needs" , "having had quite enough" , "Superabundance" .)