The last thing batter needs to stop collapse? (8)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

last letter of batteR inside (to stop) GO UNDER (collapse), &lit. A grounder is a delivery in cricket that stays low and may lead to a dismissal. Anyone who has followed The Ashes will not need an explanation of ‘batting collapse’, but to the uninitiated it’s when several batsmen are dismissed in quick succession.