Arthur of tennis (4)
I believe the answer is:
ashe
'arthur of tennis' is the definition.
(I've seen this in another clue)
This is the entire clue.
(Other definitions for ashe that I've seen before include "Arthur, who came to court" , "Arthur ___, American tennis player 1943-1993" , "US court star" , "tennis champ" , "He was good enough to win Wimbledon" .)