Sunday Times

[frameshift]

Once again only a few, that I can't see.
6d Game with poor player (6) R - B - I - RABBIT? Why?
18a Usually is beaten hollow (4) D - U - DRUM?
27a Concluded most of the series caused discomfiture (9) O - E - T - R - W OVERTHREW? OVERTHROW, wrong tense.
All help appreciated.

[Jumbuck]

6d rabbit - Chambers: Brit colloq a poor performer in any sport or game.

18a drum - dictionary.com: any hollow tree or similar object or device used in this way [like a drum]

27a perhaps 'caused' is part of the subsidiary leaving the definition as the one word 'discomfiture'

[kalahari12]

27ac over th(e) row

[frameshift]

Thanks to you both, I can get on with my chores now. Have a good Sunday.

[bathtub]

Chambers gives 'rew' as a Spenserian variant of 'row'. So there's an argument to be made for both answers (though I suspect overthrow is more likely, because this is the ST regular cryptic, not Mephisto)