Score 100% on (3)
I believe the answer is:
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">score 100% on</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for ace that I've seen before include "strained" , "Winning serve; hole in one" , "Playing card with a single symbol" , "Outstanding" , "One in playing-cards" .)