Big tournaments (5)
I believe the answer is:
opens
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">big tournaments</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 opens that I've seen before include "competitions welcoming all-comers" , "expands" , "Exposes, begins" , "Removes a lid, say" , "Unlocks" .)