River Plate missed the chance to go top of the Argentine standings Sunday with a surprise 2-0 home loss to lowly All Boys.
Emanuel Gigliotti opened the scoring for All Boys in the 37th minute after outpacing the River defense and hitting a diagonal shot into the bottom corner from the edge of the box.
Juan Rodriguez added a second in stoppage time to leave River on 22 points from 13 matches, two behind leader Velez Sarsfield. Velez plays Banfield on Monday.
Godoy Cruz is second with 23 points, while Olimpo is third, above River on goal difference.
River's arch rival Boca Juniors fared better, winning 2-0 at Argentinos Juniors with first-half goals from Martin Palermo and Juan Roman Riquelme.
Palermo stooped to head the first goal after Argentinos goalkeeper Nicolas Navarro pushed a shot straight at him in the fourth minute.
Riquelme hit the second with a low free kick that bypassed a badly positioned defensive wall in the 21st.
Boca, which hosts River next Sunday in Argentina's ''superclasico,'' has 18 points in 11th spot.
Also Sunday, Estudiantes' title defense faltered again with a 0-0 draw at Lanus, despite the home side losing Mario Regueiro to a red card in the 65th minute.
The reigning champion is now a place below Boca on the same number of points.
San Lorenzo visited Independiente in a late match.
In Friday and Saturday results it was: Newell's Old Boys 1, Godoy Cruz 3; Quilmes 2, Gimnasia 2; Huracan 1, Olimpo 2; Tigre 3, Colon 0; Arsenal 1, Racing Club 2.
