Tied the score with a regular fellow (6)
I believe the answer is:
evened
'tied the score' is the definition.
(I've seen this in another clue)
'with a regular fellow' is the wordplay.
'with' means one lot of letters go next to another.
'a regular' becomes 'even' (I've seen this before).
'fellow' becomes 'ed' (short for Edward).
'even'+'ed' is 'EVENED'.
(Other definitions for evened that I've seen before include "Made smooth and regular" , "Made level" , "Levelled" , "Made smooth or equalised" .)