Maybe extra keen on encounter (3,4)
I believe the answer is:
run into
'encounter' is the definition.
(synonyms)
'maybe extra keen' is the wordplay.
'maybe extra' becomes 'run' (extra is a type of run in cricket).
'keen' becomes 'into'.
'run'+'into'='RUN INTO'
'on' is the link.
(Other definitions for run into that I've seen before include "Meet (a person) by chance" , "Happen to meet - with a bump?" , "Encounter by chance - or collision?" , "Come across, encounter" , "charge?" .)