Make up for time lost? Excellent (1-3)
I believe the answer is:
a-one
'excellent' is the definition.
(I've seen this in another clue)
'make up for time lost?' is the wordplay.
'make up for' becomes 'atone' (I've seen this in another clue).
'time' becomes 't' (abbreviation).
'lost?' suggests deleting specific letters.
'atone' with 't' removed is 'A-ONE'.
(Other definitions for a-one that I've seen before include "First class!" , "Of the highest quality" .)