The battle between the Mexican top-flight's two most successful clubs was one-sided as America crushed Guadalajara 4-0 in the 'El Clasico de Clasicos'.
Luis Gabriel Rey netted a brace in the opening 15 minutes at the Estadio Omnilife before Raul Jimenez and Luis Mendoza scored after the break.
But Sunday's derby was the highlight of matchday 13 and America needed just 15 minutes to take control.
Cruz Azul's advantage at the top has been cut to just a point after yet another loss, the latest at home to Atlas.
Marco Fabian had cancelled out Martin Barragan's third-minute opener and the hosts looked the more likely to go ahead.
Toluca closed in on Cruz Azul after Raul Nava's 90th-minute winner saw them past Tigres UANL 2-1.
Oribe Peralta's brace helped Santos Laguna to a 2-1 win over Pumas UNAM while Veracruz overcame Pachuca 3-1.
Ricardo Jesus netted twice in Queretaro's 2-1 win over Tijuana, Monterrey held on for a 3-2 win over Atlante and Chiapas edged Morelia 1-0.
