Pumas and Toluca picked up key victories on Sunday.
Pumas and Morelia were separated by three points entering Sunday but after the weekend's games were up, only one side stood the victor.
Francisco Palencia's goal gave Pumas a 1-0 victory that sent Pumas five points clear in the overall league standings as Pumas have 24 points. Tigres sit on 19 while Morelia and Cruz Azul are on 18 points.
Palencia's goal came in the second half as Leandro Augusto fed Palencia after a failed Morelia clearance on a corner kick. Palencia dived and re-directed the cross into the goal, despite protests that he was offside. The goal was his first in 11 months.
Morelia, meanwhile, raised the pressure on the visitors after the goal but Pumas held firm and did not give up much to Morelia.
Toluca 3, Santos 1
Toluca scored twice in the first five minutes as los Diablos Rojos cruised to a victory in Estadio Nemesio Diez.
Jaime Ayovi scored in the first minute while Diego Novaretti bagged a goal in the fifth minute to give Toluca a commanding early lead.
Santos' Oribe Peralta sliced the lead in half just before halftime but Emmanuel Cerda iced the game with a goal one minute from the end of regulation.
The win pushed Toluca to within one point of America in Group 2, as los Diablos have 15 to America's 16. Santos, meanwhile, remained on 10 points and in last place in the Group 1 table.