Supervening event as exception to final, immutable judgment

It is settled that there are recognized exceptions to the execution as a matter of right of a final and immutable judgment, and one of which is a supervening event.In Abrigo v. Flores,[1] the Supreme Court said:
We deem it highly relevant to point out that a supervening event is an exception to the execution as a matter of right of a final and immutable judgment rule, only if it directly affects the matter already litigated and settled, or substantially changes the rights or relations of the parties therein as to render the execution unjust, impossible or inequitable. A supervening event consists of facts that transpire after the judgment became final and executory, or of new circumstances that develop after the judgment attained finality, including matters that the parties were not aware of prior to or during the trial because such matters were not yet in existence at that time. In that event, the interested party may properly seek the stay of execution or the quashal of the writ of execution, or he may move the court to modify or alter the judgment in order to harmonize it with justice and the supervening event. The party who alleges a supervening event to stay the execution should necessarily establish the facts by competent evidence; otherwise, it would become all too easy to frustrate the conclusive effects of a final and immutable judgment.[2]

[1] G.R. No. 160786, June 17, 2013.

[34] Abrigo v. Flores, supra, at 571-572. (Italics in the original)