Racing, looking more like members of Argentina's "Big Five" clubs than they have for years, came from behind in the "Chocolate Box" with goals by captain Claudio Yacob and Paraguay defender Marcos Caceres.
The win put Racing, who beat promoted All Boys last weekend, top of the Apertura championship standings alongside Banfield with a maximum six points.
Boca went ahead after 10 minutes with a fine headed goal by striker Lucas Viatri, his second of the championship, at the end of the home team's best move of the match involving Argentina World Cup wing-back Clemente Rodriguez.
Five minutes into the second half, Caceres, lucky not to be sent off for a bad foul on Viatri, pounced on a mistake by Rodriguez to blast the winner into the roof of Cristian Lucchetti's net.
"We took time to settle and had talked about the dangers of the opening 15 minutes at this ground," said Racing coach Miguel Angel Russo, who trained Boca in 2007.
"We took a heavyweight rival who are contenders for the title out of our path and I liked the attitude of the players. But we're still a long way from what I want from the team," he told TV Publica.
Banfield, who beat promoted Olimpo 2-1 in their opening match, won 1-0 at Colon in Santa Fe province on Friday with striker Cristian Garcia's second goal of the championship.
