An eventual national champion sustains its only loss of the year. A Mid-American Conference team goes on the road and scores twice as many points as its Big Ten opponent. A celebrated former player who is now the athletic director materializes on the sideline and argues with the referees. A lower-tier team accomplishes one of the biggest upsets in history.

These notable events, all from the last several years, share something: They all took place during the second week of the college football season. November may be college football’s crucible. Week 2 is its witching hour.

Here is a breakdown of the big Week 2 upsets from the past five years:

■ Three Football Championship Subdivision teams defeated teams from the better-resourced Football Bowl Subdivision.

■ Eight Mid-American Conference teams beat power-conference opponents.

■ A ranked Arkansas team lost to Toledo in Little Rock, Ark.