One more thing - this algortihm would naturally be executed whenever a game in the torunament was finished and a winner was not already determined for that section.
By the way, all the elements required for the algorithm to work are already accessed when a game is over - when you get a message warning you of the game's outcome, those elements are all there - points per player; games still pending per player; section winner (if already determined).

(CORRECTION as of some hours ago, I have more active tournaments than active games)