Despite an 11-game unbeaten run to begin the campaign, Real Potosi are only a point clear at the top after their 2-0 victory at Wilstermann on Sunday.
Julio Cesar Baldivieso's side have drawn six times but they were never in any real trouble at Wilstermann's Estadio Felix Capriles.
Limbert Mendez headed in a 16th-minute opener and there were few other clear-cut chances before the visitors sealed the points in the dying stages.
Freddy Chispas' strike from the left went in at the near post, securing the victory for Real Potosi.
Nacional Potosi's second victory of the season came in thrilling fashion as a stunning second half saw them beat Aurora 3-2.
Visitors Aurora looked on track for a comfortable win as Santos Amador headed in the opener and Eduardo Vallecillo tapped in a set-piece in the first half.
The hosts' recovery at the Estadio Victor Agustin Ugarte started seven minutes into the second half as Bryan Aldave drilled a penalty down the middle.
Rodrigo Vargas' low 20-yard free-kick on 78 minutes found the bottom corner – and went through the net – to draw Nacional level.
Aldave headed in the winner in the 86th minute to see Nacional move within three points of 11th-placed Wilstermann.
Second-placed San Jose stayed a point behind top spot after staging a comeback of their own to beat Guabira 4-3.
San Jose trailed 3-1 at half-time before second-half goals from Marcelo Gomes, Hector Calderon and Carlos Neumann saw them to their win.
Club Universitario slipped two points behind Real Potosi after only managing a 1-1 draw at home to Sport Boys.
Jair Reynoso's 90th-minute winner saw The Strongest claim their second straight victory by beating Blooming 2-1, while Gualberto Mojica's hat-trick led Oriente Petrolero to a 4-0 thrashing of Bolivar.
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