Racing lose again while waiting for Matthaus
Central defender Juan Insaurralde poked the ball home in a goal-mouth melee in the 69th minute after a corner to send Newell's top of the Apertura standings at least for a few hours before Estudiantes' visit to Godoy Cruz in Mendoza.
Newell's midfielder Cristian Sanchez Prete was sent off a quarter of an hour from the end for a second yellow card offence but numbers evened out as Racing's Marcos Caceres went off injured with all three substitutions made.
Racing announced at the weekend that former German captain and Salzburg coach Matthaus would arrive in Buenos Aires this week to take charge of the ailing team, one of Argentina's so-called big five.
Newell's have 23 points from 11 matches after three wins in a row. They are two points ahead of the weekend's leaders Colon, who visit Independiente on Wednesday, and three above Estudiantes who have the better goal difference.
Racing, who have been under caretaker Juan Barbas for the last three matches since Ricardo Caruso Lombardi resigned as coach, have five points and no wins.
Independiente on Wednesday will inaugurate their revamped stadium, renamed Libertadores de America after their record seven South American club titles, after nearly three years of playing home games at borrowed grounds.
Their joy was soured on Tuesday when half a dozen armed vandals smeared parts of the stadium with light blue and white paint in an attack thought to have been by hardcore fans of their arch-rivals Racing - who play in blue and white.
Racing, however, expressed their disgust and solidarity with Independiente whose stadium is within view a stone's throw across wasteland in the Buenos Aires suburb of Avellaneda.