Lanus beat Tigre 3-0 and Olimpo won 1-0 at Argentinos Juniors on Saturday as both clubs moved into the leading pack atop the Argentine league standings.
Silvio Romero scored a hat trick to move Lanus to 26 points from 15 matches, while Martin Aguirre netted a late winner to leave Olimpo a point further back on 25.
Velez Sarsfield and Godoy Cruz lead the table with 27 points. Godoy Cruz drew 1-1 at Banfield on Friday, while Velez plays its game in hand against Gimnasia La Plata on Sunday.
Meanwhile, the match between Huracan and defending champion Estudiantes was abandoned after just over 30 minutes when a riot broke out between the rival sets of fans.
Home side Huracan, which is in relegation trouble, was losing 2-0 when fans from both sides began throwing projectiles including rocks and seats from the stands.
Argentine football authorities will need to decide whether to replay the match and whether the clubs will receive punishment for the melee.
Later Saturday, Independiente had a 3-1 home win against Colon with first-half goals from Facundo Parra and Patricio Rodriguez and a late third from Nestor Silvera.
Esteban Fuertes pulled a goal back for Colon in the 64th, but Independiente held on to move into the top half of the table.
Colon slipped a place to 11th.
Romero clipped home his first goal against Tigre after Guido Pizarro's defense-splitting pass in the 16th minute.
The striker added a second with a diagonal drive into the bottom corner in the 50th and completed his treble with another first-time finish inside the box in the 57th.
Tigre remained in midtable following the loss.
Aguirre finished off a counterattack with a low shot from the edge of the box to score the decisive goal for Olimpo against Argentinos Juniors in the 85th minute.
The win preserved Olimpo's title chances, while Argentinos lost ground, staying on 22 points.
The 15th round of matches continues Sunday, with River Plate hosting San Lorenzo and Boca Juniors traveling to Arsenal.
The two traditional powers of Argentine football still harbor faint hopes of contending for the title, although River has faded recently and lost 2-0 to Boca in last Sunday's ''superclasico.''
River has 22 points from 14 games, while Boca has 21.
Also Sunday, Velez hosts Gimnasia and Racing Club travels to Quilmes.
In another Friday match, bottom club Newell's Old Boys won 1-0 against All Boys.
