Such is the appetite for football in Mexico that two tournaments are held every season in the Primera División: the clausura (closing) and apertura (opening).

So far, so relatively simple. Things get a bit trickier when it comes to deciding which team gets relegated, though. At the end of the season, the team with the lowest points-per-game-ratio over the last three seasons (six tournaments) gets relegated.

And so, in 2001 Atlante topped their group in the clausura tournament, but due to their poor form over past seasons were staring relegation in the face. Luckily for them, the league introduced a relegation play-off that season, which they won and their survival was ensured.