Fierce rivals River Plate and Boca Juniors shared two goals and two red cards in Argentina's Apertura on Sunday.
Lisandro Magallan gave visiting Boca a 22nd-minute lead but they had international midfielder Fernando Gago dismissed four minutes before half-time.
River Plate preserved their unbeaten record with a goal from German Pezzella 12 minutes from time - just two minutes after his introduction to the action. However, the pacesetters also finished the Superclasico with 10 men as a result of Ramiro Mori's 84th-minute sending off.
Estudiantes moved up to fifth and ended their dismal away record with a 2-1 victory at struggling Olimpo. El Leon had lost all four of their previous outings but won this match through Jonathan Schunke and an own goal from Nestor Moiraghi. Although Moiraghi broke through at the right end six minutes later - Olimpo's quest for a late equaliser was not helped by the dismissal of Cristian Villanueva four minutes from time.
Bottom club Quilmes and fourth-placed Newell's Old Boys drew 1-1 in the other Apertura match played on Sunday. Ruben Rodriguez gave the visitors a 33rd-minute lead, with Gonzalo Klusener levelling eight minutes later.
Source: FIFA.com