Bayern Munich's shock 2-1 defeat at RB Leipzig on Sunday saw the runaway Bundesliga leaders beaten for the first time in 19 games dating back to November.
Goals by Leipzig stars Naby Keita and Timo Werner cancelled out Sandro Wagner's opener as Bayern's lead remained at 17 points from second-placed Schalke.
Elsewhere, Eintracht Frankfurt closed in on a first Champions League/European Cup appearance since 1960.
Here is what we learned from the 27th round of Bundesliga matches:
Lewandowski Real rumours persist
Robert Lewandowski was a late Bayern replacement at RB Leipzig, but rumours of a move to Real Madrid are hounding the Poland striker.
Spanish newspaper El Mundo reported Lewandowski has agreed a two-year deal with Real to earn 16 million euros ($19.6 million) a year.
But Munich-newspaper Muenchner Merkur claim Real president Florentino Perez has told Bayern boss Karl-Heinz Rummenigge he has neither met with Lewandowski's agent nor is there an agreement.
Lewandowski, 29, has scored 32 goals this season and has a contract with Bayern until 2021 and the German club are standing firm.
"We would ask the player, 'can you read how long your contract lasts?' -- that would end the discussion," said Bayern president Uli Hoeness.
Champagne on ice
Bayern's defeat at Leipzig puts the Bundesliga title champagne back on ice for at least a fortnight.
Bayern could have sealed a sixth straight title with a win at Leipzig on Sunday, providing other results had gone their way, but those hopes were ended before kick-off after Schalke beat Wolfsburg on Saturday.
However, Bayern can still be confirmed champions by beating Borussia Dortmund at the Allianz Arena on March 31, providing Schalke fail to beat Freiburg in Gelsenkirchen.
Historic relegation beckons
Of the 16 Bundesliga clubs when the league started in 1963, Hamburg are the only one never to have been relegated -- but that record is in danger.
Their 2-1 defeat at home by Hertha Berlin left them rooted to the bottom of the table.
They have seven games to bridge the seven-point gap to safety, but the club is in a mess.
Hamburg have had three head coaches since January and Christian Titz, the latest charged with turning things around, lost his first game.
Titz ditched experienced Greek defender Kyriakos Papadopoulos and fielded the youngest Hamburg team since 1974, with an average age of 24.
After the final whistle, Hamburg fans rioted at the final whistle, fighting among themselves and with police.
Frankfurt eye Champions League
Ghana midfielder Kevin-Prince Boateng scored in Eintracht Frankfurt's 3-0 home win over Mainz to move into the fourth and final Champions League spot.
If they finish the season in the top four, it would be Frankfurt's first appearance in Europe's elite competition since losing the 1960 final to Real Madrid in Glasgow.
"We're still a bit far away from that, but if it keeps going like it has done, we'll deserve to be up there," said Boateng.
After being overlooked by Germany on Friday, Mario Goetze struggled to make his mark over 90 minutes in Borussia Dortmund's 1-0 home win against Hanover.
Goetze, whose extra-time goal won the 2014 World Cup final, has struggled in recent weeks and was left out of Germany's upcoming friendlies against Spain and Brazil.
He was replaced at half-time as Dortmund were dumped out of the Europa League by Salzburg on Thursday.
But Michy Batshuayi scored a superb first-half winner against Hanover with a stunning backheeled volley, and Dortmund hope Goetze can get back to his best.
"It was clear to us that he will get a chance to show he can do better," said Dortmund coach Peter Stoeger.