Managed a single marathon? (3)
I believe the answer is:
run
This clue is a triple definition!
'managed' is the first definition.
(I've seen this in other clues)
'a single' is the second definition.
(cricket)
'marathon?' is the third definition.
(marathon is a kind of run)
(Other definitions for run that I've seen before include "Move at speed" , "Control" , "Organize" , "escape" , "Chicken enclosure" .)