Second round — well average (2-2)
I believe the answer is:
so-so
'average' is the definition.
(I've seen this before)
'second round well' is the wordplay.
'second' becomes 's' (common abbreviation).
'round' becomes 'o' (round can mean a round object).
'well' becomes 'so' (both can mean extremely).
's'+'o'+'so'='SO-SO'
(Other definitions for so-so that I've seen before include "Only moderately good in repetitive way" , "OK, but nothing special" , "Rather middling" , "Native of Seville" , "Of average quality" .)