Anticipation supporting Oxford rowers perhaps, catching rivals in the end (9)
I believe the answer is:
foresight
'anticipation' is the definition.
('foresight' can be a synonym of 'anticipation')
'supporting oxford rowers perhaps catching rivals in the end' is the wordplay.
'supporting' becomes 'for'.
'oxford rowers perhaps' becomes 'eight' (a rowing crew can be called an eight).
'catching' is an insertion indicator.
'in the end' says to take the final letters.
The final letter of 'rivals' is 's'.
'eight' enclosing 's' is 'esight'.
'for'+'esight'='FORESIGHT'
(Other definitions for foresight that I've seen before include "Anticipation" , "Vision" , "Clairvoyance" , "Prudence" , "Ability to anticipate" .)