The contract was 4 spades and declarer ruffed the opening heart lead. He then went to the 10 of spades, led a club, finessing the 10 into West's ace. Back came another heart, also ruffed. Declarer overtook the king of trumps with the ace and led another club to his jack, ruffed by West, and now ruffed a third heart with the closed hand's last trump. Now he led the king of diamonds, won a diamond return and ran clubs, discarding a low diamond, winning the last trick with dummy's last trump, making his contract.
"What about an overtrick," dummy is alleged to have said. "That man got a trump he didn't deserve." Well, now! There are complications here apparently beyond the scope of dummy's mentality. How do you handle three forces in hearts on a modest 5-3 trump suit? How do you do so when the hand with 5 trump depleted to 2 is the one where you need entries? I'll tell you how you do it: very carefully. Anyone who thinks the key to the hand, much less an overtrick, is to draw all West's trump is going to wind up with the short end of the stick here.
How about if he guesses the stiff ace of clubs, so that he need take the finesse only once? Oh, come on. Actually, it looks to me as though he'd still have trouble, for though he could run 5 spades and 4 club winners, he'd never get a diamond winner for his tenth. Given the defensive capability of three heart forces (if declarer is to knock out the ace of diamonds), declarer can only concede a trump trick in addition to two aces in order to pick up his 10 winners, which are three clubs (one is ruffed), a diamond and six spades (three ruffs in the long hand, 3 spades in the short).
In any event, given a rough equality of knowledge about bridge, the declarer will almost certainly know more about a hand than dummy. He's the one who has to figure out his winners, which doesn't mean he's always right vis-à-vis partner, but probably so.