Fifth-placed All Boys missed the chance to move level on points with Argentinian Clasura leaders Estudiantes on Saturday night as Lucas Castroman's hat-trick condemned them to a 3-0 defeat at Racing Club.
Castroman put the hosts in control with two first-half strikes and the visitors' hopes of getting back in the game were dealt a blow on the hour mark when substitute Matias Perez Garcia was sent off. Castroman completed his treble 10 minutes from time.
Elsewhere, San Lorenzo joined opponents Belgrano Cordoba on seven points thanks to a 2-1 away win over the eighth-placed side.
Belgrano went ahead after 10 minutes through Matias Gimenez but the visitors turned the match on its head after the interval with goals from Pablo Alvarado and Nestor Ortigoza.
Argentinos Juniors and San Martin San Juan battled out a 1-1 draw, Gaston Caprari securing a point for the sixth-spotted visitors with a second-half equaliser after Cristian Grabinski's own goal had put the hosts ahead in the 26th minute.
Argentinos had Nereo Fernandez sent off 14 minutes from the end but held on for the draw.