Not disputed (12)
I believe the answer is:
unchallenged
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">not disputed</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for unchallenged that I've seen before include "not disputed" , "Not rivalled" .)