Champions Bayern languish in 12th place in the Bundesliga after Sunday's loss, 13 points behind surprise leaders Mainz. The Bavarians have scored only five goals in seven games, conceded eight, and have suffered three defeats.
"The board of Bayern has called off the planned visit of coaches and players to the Oktoberfest this lunchtime," the club said in a brief statement.
"Because of the current sporting situation coach Louis van Gaal has set a training session instead."
Club chairman Karl-Heinz Rummenigge welcomed Van Gaal's decision to organise an extra training session and gave his full backing to the coach, who signed a one-year extension to his contract at the end of last month.
"When you lose it is not proper to be (at the Oktoberfest) and raise our beer glasses," Rummenigge told reporters.
"For the coach to schedule a training session is the logical consequence. We have to be working hard now and not celebrating."
"Whether a coach is doing a good job or not cannot be determined by just one weekend," Rummenigge added. "He has our full trust."
Bayern's rocky start to the Bundesliga is in contrast to their Champions League campaign, with last season's finalists in top spot of Group E after two wins.
