Declarer ruffed the opening lead, went to the K of spades, took the spade hook, leading the J, followed by a heart to the Q, West showing out, of course. The hand would seem to be a piece of cake at this point, subject to a not-too-unbalanced club distribution. Declarer would seem to have just one spade loser and of course the A of clubs to lose, allowing declarer control of the next three rounds (round 4 being a ruff), or in other words, declarer should make on clubs being no worse than 4-2, the odds for which are up in the 80's.
Now, after the second round of trump and ostensibly to ruff a club twice in dummy, declarer led a club to the J, East taking it with the A, coming back with a spade. The hand then looked like this:
8 3
10 9
J 7
6
J 10
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K
Q 9 5 3
K 10 8
10
9 8 5
7
A 8
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K Q 4 3
Declarer now cashed the K and Q of clubs and ruffed a club. Everything's coming up roses. The hand now looks like this:
8
10
J 7
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J 10
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K
Q 9
K 10 8
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7
A 8
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4
Declarer, of course, only needed to draw the last trump, cash the last club and concede a spade. But for some cockamamie reason, he led a diamond to ruff and led the last club out, which should've been a winner in its own right, ruffing in dummy, getting overruffed! East now pounced on his opportunity to force declarer with a top diamond, and declarer now had to cough up a spade trick for down one.
Just plain poorly played. Declarer, incidentally, had sluffed a spade on the third round of clubs. The last club was a winner, as just mentioned, and had declarer merely sluffed another spade on that last club, for he hardly needs to ruff it, he would have come out smelling like a rose, giving up a ruff to the K of hearts, in return, avoiding a spade loser. The closed hand's last spade would then be ruffed in dummy with the 10, which declarer had wasted ruffing a winner.