Zia played as you did through the first two tricks — and most of the field in the tournament next played the ♦ A and the ♦ Q, which would work if the diamond suit had been 3-2.
Zia looked deeper into the deal. What would happen if diamonds were 4-1? West could hold up the king and declarer would take only eight tricks unless spades were 3-3, which they weren’t.
So Zia led the ♦ Q at trick three instead of the ace — and it didn’t matter what West did. If he held off, Zia would switch to spades, giving up a trick in the suit to make his contract with four spade tricks, three diamonds, one heart and one club.
West actually won the ♦ K and switched to a club, but Zia still had his eye on the ball. He won the ♣A, unblocked the ♦ ;A, came to hand with the ♠Q and made his contract with four diamonds, three spades, the ♥K and the ♣A. The full deal: