Old Boys slip allows Boca to move clear
Santiago Silva got the only goal in the 36th minute as Boca saw off Colon Santa Fe, with Moreno y Fabianesi's late dismissal capping a bad day for the visitors.
Newell's Old Boys needed a last-minute goal from Martin Tonso to earn a 1-1 home draw against All Boys, who had led through Mauro Matos' fifth-minute effort.
The visitors had Juan Rodriguez dismissed 11 minutes into the second half, although the numbers were evened up five minutes from time when substitute Guillermo Ortiz also saw red.
Independiente climbed into the top half with a 2-0 win over Banfield. However, the home side left it late before seeing off their second-from-bottom opponents, with Osmar Ferreyra and Ernesto Farias netting in the last 19 minutes.