a slam from Stara Zagora

So, we're back from Stara Zagora Bridge festival. Not much bridge we played there, but except this, everything was cool and we plan to go again next year.

I have two interesting slams from there. In one of the pairs sessions, me and my partner had:

♠ K10xx
♥ Kxx
♦ AQx
♣ QTx

♠ x
♥ AQJTxxx
♦ Kxx
♣ Ax

and we bid (from South, opps pass): 1♥ - 1♠ - 3♥ - 4♦ (cue) - 4NT (keycard) - 5♥ - 6♥. Probably not the best slam in pairs, but we usually like to bid slams. Now, left hand opponent leads a club. Thinking, thinking... What do you play from dummy?

I have spend some minutes on trying to see if I have any clue, however small. Ultimately, I thought we'll probably have the same bidding without the ♣10 and decided to ignore that card, playing Q from dummy. Winner ;-)

Our teammates (this was the pairs contest) made the same slam, doubled, on spade lead! How did this happened? Small spade lead, 10 from dummy, Q from the opponent who then tried to cash the ♠A too. And they call me lucky...