In my opinion there were three errors when this deal was played: a bidding error, a declarer play error, and a defensive error.
Check out the bidding first. Before you look at my opinion, who do you think made the error?
I don’t like South’s bid of 3C. North showed the major suits with no extras. From South’s perspective it is a misfit, and time to get out. But the better sign-off is to take the suit preference to two spades. North will be happy you stopped at the two-level. And North will like your two spade honors.
Now you are South in three clubs. (Suggest you print the NS hands to more easily follow the play.) Can you hold it to down one? West led the ace of diamonds followed by the king of diamonds at trick two. The eight of hearts then went to East’s jack. East continued with the ace of hearts. You trumped with a low club and led a low club to dummy’s ace as the queen fell from East. Back to your hand with the king of spades. Then the jack of clubs revealed the 5-1 break. West wins the king and exits with the four of hearts. How do you play from here? (Cover up the EW hands and see if you can avoid South’s error.)
Give it some thought before reading my recommendation.
The key is to make sure that West is on lead (end played so that she will be forced to exit with a trump from 9-6 to your 10-8. Do that by cashing the queen of diamonds and ace of spades. Then lead the queen of spades, discarding the nine of diamonds from hand. West will be in and forced to lead a club at trick 12.
The actual South did not do that. Instead, South cashed the 10 of clubs and had to lead the nine of diamonds at trick 12. Thus losing the last two trick to the 10 of diamonds and nine of clubs. The mistake cost EW a top board in a pairs game: Plus 100 instead of plus 50 by most of the field.
West erred on defense, however. West trumped the nine of diamonds, crashing East’s 10. And West had to give up a trick to South’s eight of clubs. Painful to watch.