Begin tennis tournament? (4)

I believe the answer is:

open

I believe this is a double definition.

'begin' is the first definition.
(both can mean to start)

'tennis tournament?' is the second definition.

(Other definitions for open that I've seen before include "Undo; ajar" , "Frank and unlocked" , "Sports contest" , "Candid - ready for business" , "still in debate" .)

I've seen this clue in The Everyman puzzle in The Observer.

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