First, the actual events at the table. South opened One No-trump (16- 18 points) and North raised directly to game. West led !6 against Three No-trumps - an unattractive start but, with so many high cards, he felt that he would have to lead the suit sooner or later - and East's queen was overtaken by the king.
Even if the spade finesse was right, there were only eight tricks without touching the diamonds, so at trick two declarer led a sneaky #5 from hand. West, however, could count: once his partner had produced !Q, he could have at most a jack elsewhere. So West went in immediately with #A and laid down !A - perhaps his partner had started with !Q,10,x,x,x. Well, the ten fell and West played off !J and !9. That, however, was the end of the story and East's !5 was born to blush unseen.
The unusual play that might conceivably have led to South's defeat would have been for East to contribute a low card to the first trick. Now, if the play goes in the same way (a big if!), he can overtake !9 with his queen and cash the five for the setting trick.
In case you adopt this sort of play in future, look out! West might easily have led !6 from, say, !K,J,9,6 and then playing low at trick one would not prove a popular move.