US sportsman ultimately losing in row with some clubs (5,5)
I believe the answer is:
tiger woods
'us sportsman ultimately losing' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.
'in row with some clubs' is the wordplay.
'in row' becomes 'tiger' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'with' is a charade indicator (letters next to each other).
'some clubs' becomes 'woods' (wood is a kind of club).
'tiger'+'woods'='TIGER WOODS'
Can you help me to learn more?
(Another definition for tiger woods that I've seen is " Golfer - God swore it (anag)".)