Boca Juniors slumped to a 3-2 defeat at Argentinos Juniors in the Argentine championship on a weekend overshadowed by the postponement of River Plate's match because of hooligan fears.
River's game at home to Newell's Old Boys was called off on the orders of a judge on Saturday over worries about possible trouble between rival factions of the team's supporters.
The decision came after Gonzalo Acro, identified as a leading member of the hardcore River Plate supporters club known as "Los Borrachos del Tablon, died on in hospital on Thursday, two days after being shot.
Police are investigating whether the incident is linked to a long-running internal feud in the group.
Boca, the reigning South American champion, was left with one point from two games after its defeat at Argentinos.
Pablo Ledesma gave Boca a 14th-minute lead but Alejandro Delorte equalized one minute later and Roberto Battian put the hosts ahead three minutes after the break.
Ledesma leveled for Boca with a 54th-minute penalty but Battian's second goal, in the 73rd minute, gave Argentinos the points.
Independiente, Estudiantes and Velez Sarsfield all have maximum points from their opening two games.
Diego Simeone's Estudiantes, missing midfielder Juan Sebastian Veron through injury, beat Gimnasia-Jujuy 1-0 with a late goal from midfielder Rodrigo Brana.
Independiente and Velez enjoyed 3-0 wins over Tigre and Olimpo respectively in matches played on Saturday.
Titleholder San Lorenzo picked up its first three points on Friday when it came from behind to win 2-1 at San Martin.