Libertad continued to close in on the Paraguayan Division Profesional lead as Cerro Porteno were held again.
A hard-fought 2-1 win over Deportivo Capiata saw Pedro Sarabia's Libertad extend their unbeaten league run to five games.
Fabian Balbuena and Juan Danilo Santacruz were on the scoresheet after Carlos Ruiz Peralta's surprise opener for the league's second bottom side.
Cerro Porteno are just a point clear at the top after being held to a draw for the third straight game.
The league leaders were ahead in the fourth minute against Rubio Nu thanks to Daniel Guiza, but the visitors responded immediately through Osvaldo Hobecker in a 1-1 draw.
Guarani's winless league run was extended to three matches, suffering a 3-1 loss at Sol de America.
Claudio Correa scored a brace for the victors.
Fourth-placed Olimpia recorded a 2-0 win at Nacional Asuncion as both teams finished with 10 men.
General Diaz left it late to edge 12 de Octubre 1-0, as Alberto Espinola scored a 90th-minute winner.
Sportivo Luqueno came from behind to beat 3 de Febrero 2-1.