Experienced university oarsman's back on river (9)
I believe the answer is:
underwent
'experienced' is the definition.
(I've seen this before)
'university oarsman's back on river' is the wordplay.
'university' becomes 'u'.
'back' indicates one should take the final letters.
'on' is a charade indicator (letters next to each other).
'river' becomes 'derwent' (I've seen this before**).
The final letter of 'oarsman' is 'n'.
'u'+'n'+'derwent'='UNDERWENT'
(Other definitions for underwent that I've seen before include "Was subjected to" , "Experienced; bore" .)