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.
Racing equalised just after the half hour when Yacob, who appeared marginally offside, chested in the loose ball following a free-kick.
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.
RIQUELME SIDELINED
"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.
Boca playmaker Juan Roman Riquelme, who came on before kick-off dressed in jeans and pullover to applause from the packed Bombonera having signed a new four-year contract, watched from the stands as he recovers from knee surgery.
The team coached by Argentina 1986 World Cup striker Borghi, who took charge after steering Argentinos Juniors to the Clausura title in the second half of last season, have taken one point from two matches.
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.
