Boca Juniors went top of the Clausura table with a 2-0 win at San Lorenzo in a bad-tempered match on Sunday which saw three men sent off.
Juan Mino opened the scoring for Boca in the 58th minute, and substitute Pablo Mouche sealed the points four minutes from the end.
There was a twist in the tale, though, as Carlos Bueno and Gabriel Mendez of San Lorenzo and Boca's Juan Insaurralde were sent off just before full time.
Tigre kept pace with a 1-0 win over Lanus thanks to a penalty in the third minute from Diego Morales. Lanus had Mauro German Camoranesi dismissed four minutes from time.
Union came from two goals down to draw 2-2 with Colon in the Santa Fe derby.
Moreno Fabianesi scored after 22 minutes and again 10 minutes later, but half-time substitute Diego Jara began the comeback in the 62nd minute and Nicolas Correa equalised six minutes later.
The day's other game finished goalless between Arsenal Sarandi and Racing Club, who had Patricio Toranzo sent off in the 79th minute.