Argentine striker Mauro Boselli bagged a brace as Leon routed 10-man Atlas 4-0 at the Estadio Leon on Saturday.
The comprehensive victory saw Leon (21 points, +3) move into the eighth and final Apertura play-off spot with two rounds remaining after Cruz Azul (20 points, +3), Santos Laguna (19 points, -2), Queretaro (18 points, +0) and Pumas UNAM (18 points, +0) all dropped points.
Atlas (27 points, +1) slipped from second position to fourth after losing twice in three matches.
On a three-game winning streak, Leon went into Saturday's fixture full of confidence and it took the hosts just eight minutes to assert their dominance.
Boselli made no mistake from the penalty spot, sending Atlas goalkeeper Federico Vilar the wrong way.
Leon ran rampant in the second half, with Carlos Pena heading home from close range seven minutes after the break.
Boselli had his second goal seven minutes later and Colombian substitute Yamilson Rivera got in on the action in the 68th minute, albeit with some help from a deflection.
Atlas played the final 18 minutes with 10 men following Chilean midfielder Rodrigo Millar's red card.
Leon climbed into the play-off positions after Cruz Azul played out a goalless draw with sixth-placed Chiapas, Santos Laguna drew 1-1 at third-bottom Universidad Guadalajara and Queretaro lost 1-0 to Tigres UANL (27 points, +7), who jumped to third ahead of Atlas on goal difference.
Pumas UNAM drew for the third consecutive week, held to a scoreless stalemate by Veracruz.
League leaders America dropped points for the second week in a row after drawing 0-0 against second-bottom Guadalajara in Mexico's biggest derby.
Neither side could find the back of the net in Saturday's 'El Super Clasico', despite a hectic finale at the Estadio Azteca.
America remain top of the standings with 30 points and a goal difference of +11, despite only collecting four points from a possible 12 on offer in their past four matches.
Toluca (28 points, +7) closed within two points of the pace-setters thanks to a hard-fought 1-0 win at Tijuana.
Isaac Brizuela's 25th-minute goal was all that separated the two teams, as Tijuana (17 points, +1) were dealt a blow to their play-off hopes.
In other results, cellar-dwelling Morelia stunned fifth-placed Monterrey 2-1 and Ariel Nahuelpan's penalty earned Pachuca - seventh in the table - a 1-1 draw at Puebla.
