Substitute Pablo Mouche netted the only goal of the game in the 86th minute to put Boca at the head of four teams on seven points.
They have still yet to concede in three matches, with a goal difference of five.
Racing Club are just behind them with a goal difference of four after their 1-0 win at Banfield.
They scored early through Matias Cahais (6) and held on for the remainder.
Tigre took their first victory of the season at Godoy Cruz's expense, the hosts winning 2-1.
Ezequiel Maggiolo scored twice for Tigre, once in each half.
Diego Villar pulled one back moments after Martin Galmarini's 67th-minute sending off but Godoy could not expose their opponents a second time.
All Boys fell to a 2-1 defeat against visiting Atletico Rafaela.
The home went ahead in the first minute through Mauro Matos only for Federico Gonzalez and Walter Gaitan to deliver the win for All Boys.