The Argentina winger weaved his way past two defenders on the right, turned inside another two and hit a left-footed shot low inside the near post in the 86th minute.
Newell's are top of the "Inicial" championship, first of two in the Argentine season, with 17 points from eight matches. The champions cannot be caught by Arsenal, San Lorenzo, Argentinos Juniors and Gimnasia, all with 13 points, over the weekend.
Racing, rooted to the foot of the table with two points, played better than they had so far this season and were unlucky with midfielder Rodrigo Del Paul hitting the bar and post in the space of two minutes at the end of the first half.
"I'm really angry, the players made a huge effort and we've come away with nothing ... You don't get points for merit and we need more points," Racing coach Carlos Ischia said.
Fans at the club's Cilindro stadium chanted: "They must all go, none of them can stay" against the club's board who have split into factions after the team's abysmal start to the season.