Beaten Newell's hand lead back to Banfield
Striker Franco Jara and midfielder Matias Perez scored in the first half against a nervous Newell's side.
Uruguayan Joaquin Boghossian pulled one back for Newell's. It was his tenth goal of the campaign.
There are still four teams in the race with title holders Velez Sarsfield, 3-1 winners at home to River Plate, five points behind Banfield and fourth-placed Independiente six points adrift yet clinging on only mathematically.
Banfield, who had slipped to a first defeat of the season at home to Racing Club last week that allowed Newell's to overtake them, won 1-0 at Huracan on Saturday with a goal by championship leading scorer Santiago Silva, who took his tally to 14.
In the weekend's "clasico" on Saturday, Independiente beat ailing Boca Juniors 2-1, their first victory at the Bombonera since 1996.
Boca's veteran striker Martin Palermo, who has been missing the assistance of the injured Juan Roman Riquelme, again failed to score and has now not found the net in seven matches.