You took the best line monik and the layout was such that an inferior line would have succeeded. It happens.
@Wyman: don't be a nit. It is close to a freeroll. You trade the club loser for the diamond loser and keep your options intact. You only lose if:
- The Kd is off
- They can organize a heart ruff
- They find said heart ruff
- Ks is onside and spades are 2-2
That is 4 requirements. Only if all 4 are met is the direct spade finesse the best play.