Bayer Leverkusen edged ever closer to winning their first ever Bundesliga title after they beat Union Berlin, while Bayern Munich surrendered a two-goal lead to lose 3-2 away to Heidenheim.
Bayern Munich had established a 2-0 lead before half time courtesy of goals from Harry Kane and Serge Gnabry.
However, Heidenheim managed to turn the game around, with Kevin Sessa getting a goal back before Tim Kleindienst scored a brace.
Bayern Munich have won the Bundesliga title for the last eleven years in a row, but it is looking increasingly likely that their dominance will come to an end.
Xabi Alonso's Leverkusen, meanwhile, won 1-0 away to Union Berlin courtesy of a penalty from Florian Wirtz just before half time. Union Berlin had been reduced to ten men shortly before that when Robin Gosens was dismissed.
Harry Kane scored but Bayern Munich surrendered a 2-0 lead as they lost 3-2 to Heidenheim
Florian Wirtz scored a penalty, with Leverkusen going 16 points clear after beating Union Berlin
Bayern Munich had appeared on course for victory but suffered a surprise defeat
Bayern manager Thomas Tuchel was left dejected in his post-match press conference
Leverkusen return to league action next weekend when they host Weder Bremen, with Bayern in action at home to Cologne.
Prior to that, both teams have European fixtures against English opponents.
On Thursday Leverkusen will host West Ham in the first leg of their Europa League quarter-final.
Bayern are in Champions League action on Tuesday night as they face Arsenal away in the last eight.
UEFA have informed Bayern fans that they will not be allowed to attend the game after supporters broke rules by setting off fireworks during a group stage fixture away to Copenhagen.
However, in a pointed message to UEFA, Bayern fans produced a banner on Saturday stating that they will still go to London anyway.
The banner read: 'We're going to London anyway! Wembley calling - F*** UEFA'.
This season's Champions League final is set to take place at Wembley on on June 1.
Xabi Alonso was delighted as his Bayer Leverkusen side took another step towards the title
Tim Kleindienst scored a brace as Heidenheim managed to secure an impressive victory
Kane and Gnabry were both on the scoresheet but Bayern couldn't hold on to their lead
