Neuer inexplicably allowed a Raffael effort squirm over the goalline 30 minutes into the clash at the Allianz Arena on Sunday, a setback from which Bayern never recovered.
That error came just six minutes after the forced withdrawal of the injured Arjen Robben and the Bundesliga's runaway leaders lacked fluency in the final third without their Dutch star.
Raffael doubled his tally 13 minutes from time, handing Bayern their first Bundesliga home defeat since April 2014, but it was the champions' attackers who drew the ire of Guardiola, not Neuer.
He told reporters: "We didn't lose due to Manu, but because we had problems in attack.
"It's the Bundesliga and people think it's always easy, but I know how difficult it is.
"We'll analyse the game and after the international break we'll get back to winning ways."
Neuer himself was also quick to lament Bayern's ineffectiveness in attack, acknowledging that the hosts did not deserve anything due to the simple fact that they failed to craft any clear-cut opportunities.
"Gladbach were very good and defended excellently," the goalkeeper added. "We didn't create any genuine chances. That wasn't good enough.
"Obviously we wanted to do much better and we've missed a chance because Wolfsburg dropped points [in a 1-1 draw at Mainz] today.
"But it won't darken our mood. We know what we're aiming for this season. We'll look to the future and we're optimistic."
