Bayern Munich midfielder Joshua Kimmich said his side need to question their mentality after they slumped to a shock 2-4 loss at Bundesliga minnows Bochum ahead of Wednesday’s Champions League clash with Red Bull Salzburg.

Bayern conceded four goals in the first half for the first time in a Bundesliga match since 1975 as promoted Bochum rampaged to victory, leaving the perennial champions stunned.