Perform very well (5)
I believe the answer is:
excel
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">perform very well</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 excel that I've seen before include "Be superior to" , "Be exceptionally good (at a subject)" , "Predominate in" , "Outdo" , "Be the best" .)