Boca Juniors remains at the top of the Argentinian Apertura but it was forced to come from a goal down in its 2-1 victory over Independiente.
Boca looked like it would have no problem seeing off second bottom Independiente - which is winless so far this season - but it surprisingly fell behind when Argentina defender Matias Caruzzo put the ball into his own net in the 23rd minute.
It spurred the host into action, however, with Santiago Silva equalising four minutes later and Juan Sanchez Mino scoring the winner in the 47th minute to keep Boca a point ahead of the chasing pack.
Nacho Scocco's 82nd-minute penalty ensured second placed Newell's Old Boys squeaked past 10-man San Lorenzo 1-0.
Newell's was in danger of losing ground on Boca as the match entered its closing stages but Scocco held his nerve from the spot while San Lorenzo's misery was compounded when Abel Masuero was dismissed three minutes later.
Velez Sarsfield moved up to third - just a point behind Newell's - after it eased past River Plate 2-0 in a fiery clash that saw both sides finish with 10 men.
Goals from Lucas Pratto (20) and Ivan Bella (64) sealed a comfortable victory for Velez, which had Emiliano Papa sent off in the 69th minute - just seven minutes after Ramiro Mori had seen red for River.
Lucas Pittinari's 45th-minute strike and Jorge Velazquez's last-gasp goal saw Belgrano Cordoba claim a 2-0 win at Arsenal Sarandi, which had Nicolas Aguirre sent off in the closing stages.