America – who topped the Apertura table but lost the final to Leon in December – started their bid to make amends in style with a big win at Estadio Azteca.
Colombian forward Luis Rey opened the scoring in the 10th minute and they did not look back from there, Paul Aguilar doubling their lead on the half-hour mark.
And star striker Raul Jimenez wrapped up the win four minutes from time, as Antonio Mohamed's team began their campaign with a win.
Leon were held to a 1-1 draw at Atlante in their opening game.
Carlos Pena gave Leon a 35th-minute lead, but his effort was cancelled out by Manuel Viniegra early in the second half.
Queretaro and Toluca also posted triumphs on the opening weekend, with both sides winning 1-0 on the road on Saturday.
Miguel Martinez scored the winner for Queretaro, who had to hold on in the final stages after George Corral was sent off for a second yellow card at Morelia.
Paraguay forward Pablo Velazquez got the only goal for Toluca, with his strike 15 minutes from time proving decisive at Toluca.
Other results across the weekend saw Monterrey and Cruz Azul play out a goalless draw, as did Atlas and Tijuana, while a 10-man Santos Laguna came from behind to draw 1-1 with Guadalajara.
Chiapas and Veracruz also finished at 1-1, while Puebla scored twice in injury time to draw 2-2 at Pumas UNAM.
