Lost initially in games, then was finally second to none (9)
I believe the answer is:
matchless
'second to none' is the definition.
(thesaurus)
'lost initially in games then was finally' is the wordplay.
'initially' indicates taking the first letters.
'in' means one lot of letters goes inside another.
'games' becomes 'matches' (**).
'then' is a charade indicator (letters next to each other).
'finally' says to take the final letters.
The first letter of 'lost' is 'l'.
The final letter of 'was' is 's'.
'l' inserted inside 'matches' is 'matchles'.
'matchles'+'s'='MATCHLESS'
(Other definitions for matchless that I've seen before include "Unequalled" , "reason for rubbing sticks together?" , "Unique" , "Incomparable" , "beyond compare" .)