Nacional Asuncion defeated Cerro Porteno 1-0 to jump into second in the Paraguay Division Profesional, as Libertad won again.
Libertad maintained their unbeaten start to the Paraguayan top tier with a 5-1 thrashing of Deportivo Capiata on Monday but finished round four with a new main rival at the top of the table, as Nacional leapfrogged Cerro Porteno on Saturday.
With Libertad set to play the final match of the round, both Cerro Porteno and Nacional had the opportunity to claim a temporary lead in Paraguay when they faced off at the Estadio General Pablo Rojas.
Cerro Porteno had won the past three matches between the two teams and had yet to suffer defeat in the Division Profesional's 2014 Apertura campaign.
But after a goalless first half, Nacional scored the only goal of the game six minutes into the second period with Julian Benitez getting free in the penalty area to send a diving header past the home side's goalkeeper Diego Barreto.
The victory took Nacional to nine points, while Cerro Porteno (seven points) slipped to third.
In Capiata, Libertad moved ahead of Nacional by a point to regain top spot after a stunning first half set up their victory over the hosts.
Jorge Recalde, Gustavo Gomez and Claudio David Vargas all scored in the first half for Libertad, while Rodrigo Lopez and Ivan Ramirez struck in the opening eight minutes after the break to give the visitors a five-goal lead.
While Cristian Andersen scored for Capiata in the 70th minute, Libertad were always in control and made it three wins and a draw from four games so far this season.
Rubio Nu moved to fourth spot on Sunday, level with Cerro Porteno on points, goal difference and goals scored, after a 2-1 win against Olimpia.
In a bad start for Pablo Caballero's Rubio Nu side, Olimpia took the lead in the 15th minute through Esteban Ramirez's penalty but the hosts equalised just after the half-hour mark thanks to Claudio Correa's header.
Correa was the hero for Rubio Nu in the second half as he scored the winner in the 71st minute, running onto a through ball before firing a left-footed shot into the net.
In other results, Guarani crushed Sportivo Luqueno 4-1, Sol de America cruised to a 3-0 victory against 12 de Octubre and 3 de Febrero held General Diaz to a 1-1 draw.