He was given some help when West led the club ace.
Since this was a team event, South should have continued with his club ace.
But when it did not, South called for the club ace.
After the lead of the club ace, the play became difficult.
If West held the club ace, he was sure to make it.
However, he won in his hand with the club ace and led the heart king.
But West made an effective lead of the club ace followed by the two.
The only hope was that West held the club ace.
The defense started with a heart to the king, and took the club ace.
South led to the club ace and played a second round.