Julian Nagelsmann bemoaned Bayern Munich's underwhelming performance and suggested change is needed after the Bundesliga champions succumbed to defeat at Mainz.

Bayern secured a record 10th straight league title with Klassiker victory over Borussia Dortmund last weekend but were caught cold by Mainz after first-half strikes from Jonathan Burkardt and Moussa Niakhate.

Robert Lewandowski reduced the deficit with his 18th away league goal this season, setting a Bundesliga record for a single campaign, while taking his tally to 49 in all competitions – the most of any player in Europe's top five leagues.

Leandro Barreiro Martins restored the two-goal cushion after the interval for Bo Svensson's hosts as Mainz coasted to just a second league win over an uncharacteristically poor Bayern in their last 10 attempts.

Nagelsmann expressed frustration with his side after the defeat but acknowledged a downturn in performance was to be expected after the title win.

All over in Mainz.

#M05FCB 3-1 pic.twitter.com/8bNrSs5euu

— FC Bayern Munich (@FCBayernEN) April 30, 2022

"We had too many performances and defeats of this kind this season," he told reporters.

"I have an explanation for it, but I won't give it to you. It's not for the media. I say it internally.

"After winning the 10th title in a row, it's a bit human but we still have to play for the badge on our chest.

"It seems like the passion isn't really there anymore. We reached a point where something needs to change. That's where we are right now."