The defeat was Bayern's first of the season, ending a record-breaking eight-game winning streak and opening up the title chase which had been turning into a one-horse race.
"I am sure the rest of the Bundesliga is delighted," said Rummenigge. "Particularly Schalke and Dortmund will be pleased with this result."
Schalke are now just four points behind while Dortmund's nine-point deficit is no longer looking so prohibitive.
And Bayern only need look back 12 months for a reminder as to how quickly things can change.
"November 2011 was not a good month," he told reporters at the Allianz Arena. "We have got to do better than we did then.
"We have got to show that we can cope with the pressure better than last year.
"I am curious to see whether the team does better. We have got to because the clubs behind us are now four, five or nine points adrift.
"The team will come under pressure after this defeat, and they have got to deal with it."