Rosemary, perhaps during series of games, gets a fizzy drink (7)
I believe the answer is:
sherbet
'a fizzy drink' is the definition.
(flavoured drink)
'rosemary perhaps during series of games' is the wordplay.
'rosemary perhaps' becomes 'herb' (rosemary is a kind of herb).
'during' indicates putting letters inside.
'series of games' becomes 'set' (tennis).
'herb' placed within 'set' is 'SHERBET'.
'gets' is the link.
(Other definitions for sherbet that I've seen before include "A fizzy drink, a fruit drink" , "Australian beer" , "Sweet effervescent powder" , "Fizzy stuff" , "Foreign beer" .)