Bundesliga champions Bayern Munich fell to a 3-1 defeat at Mainz despite Robert Lewandowski setting another record.

Julian Nagelsmann's side sealed a record 10th straight league title by defeating Borussia Dortmund last time out, but were soon behind on Saturday after strikes from Jonathan Burkardt and Moussa Niakhate.

Robert Lewandowski halved the arrears with his 18th away league goal this season – a new Bundesliga benchmark for a single campaign – before Leandro Barreiro Martins restored Mainz's two-goal cushion after the interval.

Bayern were unable to respond as the champions suffered just a second defeat in their last 10 games against Mainz, who moved up to ninth with victory.

Burkardt cannoned against the crossbar and the post, while the unmarked Alexander Hack was denied by the woodwork but Mainz's early dominance soon paid dividends.

Sven Ulreich thwarted Karim Onisiwo from close range yet could not stop Burkardt when the striker powered a left-footed attempt home following Dominik Kohr's headed offload.

Niakhate doubled Mainz's advantage when he tapped in after Anton Stach's flick, before Lewandowski rolled into the bottom-right corner following Eric Maxim Choupo-Moting's pass to reduce the deficit.

Barreiro Martins almost restored the hosts' two-goal lead before the interval, only for his left-footed free-kick to curl narrowly wide.

But Barreiro Martins' luck was in after the break when his strike deflected in off Benjamin Pavard.

Burkardt dragged wide and Onisiwo smashed onto the crossbar from the edge of the area as Bayern, who repeatedly appeared frail on the counter-attack, were unable to mount a comeback.

What does it mean? Bayern caught cold on the road at Mainz again

Bayern had won eight of their last nine league meetings with Mainz, though the one blemish on their record came in this fixture last season when the hosts ran out 2-1 winners.

Mainz scored first on that occasion and followed suit in this game as they opened the scoring for four straight games against the Bavarian giants – no other current Bundesliga side have achieved this consecutively more than twice.

Super Stach shines

Stach was a constant presence in the middle of the park for Bo Svensson's team, setting up Niakhate's goal – one of a game-leading seven key passes the midfielder supplied for Mainz.

Legendary Lewandowski

Despite speculation of a move away from Bayern with just over a year left on his contract, Lewandowski continues to deliver. His tally in all competitions this season now stands at 49.

No player has managed more goals in Europe's top five leagues, while the Poland international also put his name to yet another Bundesliga record.

What's next?

Bayern host Stuttgart on May 8, while Mainz make the trip to Hertha Berlin the day before.