Though they’ve already been confirmed as champions, Leverkusen were still chasing an invincible season as they faced off with Stuttgart for the third time this season.
Die Werkself started brightly too, with Jeremie Frimpong using his pace to great effect on the right, but his indecision with the final ball wasted an early chance.
The visitors grew into the game though, and almost broke the deadlock when Serhou Guirassy flashed a header just wide of the target.
At the other end, Alexander Nubel was called into action, parrying Alejandro Grimaldo’s strike into the path of Patrik Schick, but the Czech striker was off balance and volleyed over with the goal at his mercy.
Stuttgart were subdued in attack as the first half wore on, but they wasted no time putting that right after the restart, taking the lead inside two minutes of the second half.
Jamie Leweling streaked clear on the right flank and forced a save from Lukas Hradecky, who diverted the ball onto the post, but the rebound was met with a magnificent first-time volley from Chris Fuhrich into a largely unguarded net to silence the BayArena.
Although Xabi Alonso’s side have earned a reputation for their comeback ability, their invincible status was placed in real jeopardy in the 57th minute.
No team had taken a two-goal lead over Leverkusen in the league all season, but that all changed when Deniz Undav pounced to make it 2-0 to the visitors with his 18th Bundesliga strike of the campaign.
Despite a nervy silence setting in, the hosts took just five minutes to respond, as Grimaldo picked out Amine Adli to halve the deficit with plenty of time still to play.
They could’ve been level shortly afterwards, but Nubel made an incredible double save to deny Adli and then Jonas Hofmann from close range.
The hosts really started to throw everything at saving their unbeaten record, and thought they had levelled the game when Odilon Kossounou found the back of the net, but the strike was ruled out as Edmond Tapsoba was offside in the build-up.
But as they've proved so many times in recent weeks, Leverkusen simply don't know when they're beaten, and that rang true again here in incredible circumstances.
Florian Wirtz's free-kick from the left wasn't cleared, and Andrich seized on the loose ball from close range to ram home the leveller that left Stuttgart stunned.
Flashscore Man of the Match: Alexander Nubel (Stuttgart)