Mexico’s domestic cup competition, the Copa MX, is a little more complicated than most. Like the FA Cup in England or the Open Cup in the U.S., the Copa MX involves teams at different levels of the soccer pyramid. In the Clausura edition of the cup, the 11 Liga MX teams not involved in another cup competition – that is, the CONCACAF Champions League or the Copa Libertadores – face off against the 13 best teams from the Liga de Ascenso, with the 24 teams then put into 6 groups of four. In the Apertura edition, the Copa MX features 28 teams, 14 each from Liga MX and Ascenso MX, in 7 groups of four.
In the group stage, each team plays a home-and-away series with the other three teams in their group. These series are known as “Llaves” (keys) and the winner of each Llave, based on the aggregate score of the series, receives an extra point in the standings. So winning both games in a Llave will net the winning team 7 points rather than 6, and a win and draw nets 5 points instead of 4.
In the Clausura edition, the six group winners move on to the knockout rounds, as do the two best second-place teams. In the Apertura edition, the seven group winners advance as well as the single overall best second-place team. Those extra Llave points can definitely come in handy there.
The knockout rounds are one-game, single-elimination faceoffs, held at the home of the higher seed. If the games are tied at the end of the 90 minutes, the Copa MX skips directly to the penalty shootout rather than first playing 30 minutes of extra time.