An achievement, of course — yes, picked up a good looker (5,3)
I believe the answer is:
eagle eye
'a good looker' is the definition.
(someone good at observing or looking)
'an achievement of course yes picked up' is the wordplay.
'an achievement of course' becomes 'eagle' (score on a golf course).
'yes' becomes 'ay'.
'picked up' indicates a 'sounds like' (homophone) clue.
'ay' sounds like 'eye'.
'eagle'+'eye'='EAGLE-EYE'
(Other definitions for eagle eye that I've seen before include "Keenness of vision" , "Ability to observe fine detail" , "(Person with) very keen vision" , "Keen sight" , "one envisages a long way off" .)