Complex sentence: The men's national team held an unbeaten record of 8--3--0 in all competitions, outscoring opponents 19--1, until the U.S. was beaten by the Mexico national football team on Veterans' Day 2016.
Split into simpler sentences: The men's national team held an unbeaten record of 8--3--0 in all competitions, outscoring opponents 19--1. This was until the U.S. was beaten by the Mexico national football team on Veterans' Day 2016.