Source: BDI ITalia By | Apr 18, 2017 | 
Knowing the three colored West hand with a sure spade singleton I attacked (in the North position) with the 
K: the goal of the attack was to: not let declarer to win with a singleton honor and to play spade towards my partner, Margherita Chavarria (for example, singleton J to Q9543, where the A1086 in South would have guaranteed four trickes).
After watching the declarer won with the ace and play a heart to the queen, knowing that she would be willing to repeat the finesse, I played low because to repeat the finesse, she would have to use the 
Q, an entry to the table. The play went this way and I could take the second heart to cross another spade for the jack and the queen (West played a club). My partner after winning the trick, returned a club, declarer played her jack and I won with the ace, and played a spade..
At this point, the declarer had eight theoretically tricks (a spade, three hearts and four diamnods thanks to the 3-3), but still she has to discard when South plays the 10. She can not play a club because she now has 
Q x, so she had to discard a diamond, forcing her to give two clubs in the final after South’s heart return: this is an example of squeeze over declarer by the defense.
The contract could have been accomplished by playing a second heart from declarer’s hand as the defense spades would not have effect: the Q would have remained in dummy to ensure two additional spade tricks for E / W. But she would have missed the not-insignificant chance of the heart king third, that would have guaranteed eight tricks (a spade, four diamonds and three hearts) without any particular effort.
