Let’s see the declarer play first. Csaba Konkoly should have gone down in 4♠, losing a club, a spade and two diamond tricks. After North took the trick with the jack of spades, he could have played his last spade and then declarer has no chance to make the contract, but he rather played his club in hopes of a ruff. Little did he know that Konkoly also had a singleton. Ruffing the next club in his hand, declarer took the king of hearts, ruffed his small heart and played the last two spades from dummy.
He then took his high club and played a small one. East now only had to guess the spades right to make the contract. László Szilágyi knew this as well and he overruffed dummies eight with his king(!). He deceived declarer to think South has the jack of spades and alas, he tried to finesse it.