Source: 4th EUROPEAN OPEN BRIDGE CHAMPIONSHIPS June 2009, Sanremo, Italy
A brilliancy at bridge does not need to be based on perfection. The actual bid, play or defence that is involved should include a moment when something astonishing, beautiful and inspiring occurs at the table.
It might be an imaginative opening lead, (say the 
A from AQ6) an out of the blue sacrifice of a high card (such as a Deschapelles or Merrimac Coup) or an unusual manoeuvre (perhaps an Intra Finesse).
Here is a deal from the 2008 World Bridge Games where a defender combined two of the above in a single play:
Dealer North, None Vul
When South elected to lead the queen of clubs he dealt the contract a mortal blow. This was a remarkable example of a brilliant lead that was also a Merrimac Coup, destroying a vital entry to dummy’s diamonds.
It does not in any way detract from South’s brilliance that North subsequently misdefended, allowing declarer to score a couple of diamond tricks.
Brilliant declarer play frequently relies on a defensive mistake. The following deal appeared on the front cover of the May ACBL Bulletin.
The deal took place during the Bermuda Bowl in Hammamet, Tunisia, in 1997. Meckstroth’s play at trick one earned him the International Bridge Press Association Hand of the Year Award for 1998. The deal is rotated to make Meckstroth South. Did you find the key play at trick one after West started with a low diamond?
It is clear that 3NT is a much easier contract, which no doubt was obvious to Meckstroth at trick one. That fact, of course, was irrelevant – his job was to take 11 tricks in clubs.
One reason that Meckstroth won the top declarer play award is that he made his trick-one play in tempo. Smooth as silk, he called for the 
10!
Helgemo won the queen and could have scuttled the contract by switching to a spade or a heart, but it looked as though Helness had hit declarer’s soft spot. Back came a diamond – and the contract could no longer be defeated.
Meckstroth discarded the 
3 from hand, won the A and led a low heart from dummy. Helgemo played low (it would not have helped for him to play the ace). Helness took the Q with the king and fired back a spade, but Meckstroth went up with the ace and played the J from dummy. Helgemo covered with the ace, ruffed by Meckstroth. Now the 
A and a club to the king took care of the Norwegians’ trumps. The 10 went on the 10 for 11 tricks and plus 600.