Cyberyeti, on 2019-July-15, 08:01, said:
They won the K, played spades conceding one to establish the 5th one, and a club came back, now when they played a diamond to make an entry for the 5th spade, another club came back cutting them off from ♦A.
By now the defence have five tricks (the spade you lost, the diamond you lost to create an entry, two clubs and the ace of hearts, You're too late even if you get back for the ace of diamonds.
It seems to me that playing on spades will only work if they are 3-3, as you can't force an entry quickly enough.
It doesn't look like playing on hearts is any better since the second part of the question suggests that south holds
♥QJ9(X).
There doesn't seem to be any hurry to test the spades, so maybe play the club 10 as Cyberyeti suggests and duck when north plays the jack or queen (i'm not an optimist). Then play a diamond, hoping to judge an end-play later?