Lanus extended their lead at the top of the Clausura table to three points with a 1-0 win at Godoy Cruz on Sunday.
Carlos Izquierdoz scored the only goal after 27 minutes and, with River Plate slipping up, it was enough to pad Lanus' cushion at the top.
River were beaten 1-0 at Newell's Old Boys, who leapfrogged them into second place, thanks to a 36th-minute strike from Ignacio Scocco.
The other three matches all ended 1-1.
Racing Club took the lead against Belgrano Cordoba after 12 minutes, but were pegged back by Jorge Velazquez five minutes after the break.
Two goals in a minute saw Velez Sarsfield and Estudiantes share the spoils, with Federico Insua putting Velez ahead in the 77th minute and Leandro Benitez replying immediately for the visitors.
The hosts had Fabian Cubero sent off late on.
Matias Martinez scored on the stroke of half-time to salvage a point for Argentinos Juniors at Boca Juniors, who had opened the scoring through Santiago Silva's 13th-minute penalty.