Velez Sarsfield lost top spot in the Argentinian Apertura as they suffered a 2-1 defeat at Boca Juniors.
Sebastian Battaglia and Lucas Viatri got the goals for Boca with Santiago Silva's 85th minute strike not enough to help his side, who had won their first three games, earn a point. That result saw Velez replaced at the top by River Plate, who saw their own 100 per cent record ended by a goalless draw at Argentinos Juniors.
Arsenal Sarandi moved up to second place with a 2-1 win at Independiente. Sergio Sena and substitute Gonzalo Choy Gabriel put Arsenal in control before Leonel Galeano got a late consolation for Independiente.
The day's other game saw Olimpo claim a 1-0 win over nine-man Racing Club. Nestor Barreiro got the only goal of the game after 39 minutes before Racing had Matias Cahain and Patricio Toranzo dismissed in the second half.
