In the 10th of 17th round of the Round Robin, Argentina defeated Belgium 45 to 11 IMPs.
On one of the tables in E/W was Maximo Crusizio playing with Rodrigo da Rosa for Argentina and N/S Ormay-vd Hove for Belgium, in the other room N/S were Hegge-Stangeland playing for Argentina and Overmeire-Bahbout for Belgium.
Board No 1 was a double digit for Argentina: When North opened his hand with a 3
preemptive bid, East only possible bid was a double, West with his 4-3-3-3 and 6 HPC chose to replay 4
and East closed the 5 game. 
The lead was the 
4, declarer watching his two diamond losers, decided to finesse. South won the trick with his K and played another spade for his partner’s ruff. North continued with his A and watching his partners positive signal repeated a diamond, South won the trick with his K. Stangeland played another spade and North could ruff again. Next came another diamond, but declarer ruffed high to reduce his loses to three down.
On the other table North passed, what made life simpler to the Argentines. Garcia da Rosa opened with a 2 strong bid and the partnership finished in a 3NT contract. The lead was a little spade and when dummy’s 9 won the trick, declarer played another spade, when South won the trick with his K, da Rosa claimed 10 tricks and 11 IMPs for his team.
Board No 2 was a reflection of the first, Belgium played again 5 and Argentina chose 3NT, but in this case was Argentina who was two down while Belgium fulfilled his contract and won 11 IMPs.
The next important swing was board No. 6. Garcia da Rosa opened his hand with a 1 bid, and closed the 4 game when his partner supported his suit.
South lead the Q, declarer played a little club from dummy and Rodrigo ruffed in his hand. He continued with a high trump and next came the 
2 to the A and the 10 to the K and the 4.
When South ruffed with his 10, declarer pitched a little diamond from dummy. Now South had an opportunity to defeat the contract playing A and a to his partner’s K and ruff a diamond return…but he chose to play a trump to stop declarer ruffing many hearts…bad idea…
Rodrigo won with his K, ruffed a heart, now he had a good heart in his hand, lose A and K and claimed 10 tricks.
On the other table the defense was different. The lead was the A. When Stangeland saw an encouraging sign from his partner, he played another diamond. North won with his K and returned a third diamond…South ruffed and played his Q. Declarer ruffed and continued playing heart to the A and heart to the K and a heart…South ruffed with his 10 and the contract was down one and 12 IMPs for Argentina. 
Two boards later appeared another big swing for Argentina.
Maximo opened his hand with a 3 preempt bid, North passed, Rodrigo raised to 4, North doubled but they were to high to begin to find out what was their best contract…Declarer was two down -300. 
On the other table, West didnt open the bidding and opened the way for North / South to find a club slam.
The diamond lead is the only one that defeats the contract, since West remains with no diamonds and when his partner wins the first trump trick with his A he can play another diamond for West to ruff…and one down…
But at the table, the lead was the A and another club. That gave the declarer the opportunity to win the second trick with his K and play a diamond to the J , when he won the trick…he continued with the A watching West pitch the J, so he continued ruffing another diamond. He came to his hand ruffing a spade, played a trump and claimed his contract. Another 12 IMPs for Argentina.
The last board was the last thrust.
South opened his hand with a 1 bid, and the partnership arrived to a 4 contract. The lead was a heart that sealed the fate of the contract. Declarer won in his hand and played the club finesse…East won with his K. And continued with a spade, Stangeland won with his K, played trumps, and pitched all his problems in the club suit to claim 11 tricks. Very different would have been the story if the lead was a spade. 
The spade lead, allows the defense to make the A and play another spade to free the spade queen before declarer can play clubs and so defeating the contract, a diamond lead and an immediate switch to spade has the same effect.
On the other table South chose to open his hand with a weak 1NT opening bid, the partnership finished the bidding with a 3NT contract. The lead was the fourth best spade, that didnt give declarer any chance to fulfill his contract.
South won the lead with the K and continued with the club finesse, now the defense could play three spades rounds and the A for one down and another 13 IMPs for Argentina.