Josip Stanisic was on target seven minutes into stoppage time as champions Bayer Leverkusen salvaged a 1-1 Bundesliga draw at Borussia Dortmund on Sunday for a record-extending 45th match without defeat all season.
Champions League semi-finalists Dortmund thought they had won it from Niclas Füllkrug's 81st minute volley.
But Leverkusen fought back and got yet another very late goal when the glancing header from Bayern Munich loanee Stanisic off Florian Wirtz' corner went into the far right corner at the death.
The draw raises Leverkusen's unbeaten Bundesliga run to 30 matches, and to 45 all season in all competitions, both record-extending.
"It is not easy to stay mentally fresh after winning the title. But we have a challenge to go unbeaten all season," midfielder Granit Xhaka told streaming portal DAZN.
"We showed a lot of passion and just want to continue this way."
Coach Xabi Alonso said: "It feels very good. We don't want to lose. A defeat today wouldn't have been deserved. We played very well. The goal at the end was of course very emotional."
Füllkrug said: "We would have deserved to win. But now it feels lousy. We didn't allow much. It's bitter that we didn't win, Leverkusen would have deserved to lose."
No team has ever gone unbeaten over a full Bundesliga season.
Leverkusen's remaining four league matches are against third-placed VfB Stuttgart, at Eintracht Frankfurt and Bochum, and at home against Augsburg. Bochum were the last team to beat Leverkusen, in last season's finale on May 27, 2023.
They face a Europa League semi-final against Roma, plus a potential May 22 Dublin final, and are in the German Cup final against second division Kaiserslautern on May 25 in Berlin.
Dortmund in fifth slipped two points behind RB Leipzig, who they visit next week, in a fight for a top four finish guaranteeing Champions League entry. Fifth place may also be good enough and Dortmund can qualify as well if they win the elite event.
Elsewhere on Sunday, third-placed Stuttgart lost 2-1 at Werder Bremen from Marvin Duksch's brace, with Deniz Undav getting the consolation goal.
Bremen are seven points clear of the danger zone as they ended Stuttgart's unbeaten run after 11 matches and snapped their own winless run after seven matches.
European hopefuls Freiburg drew 1-1 with lowly Mainz from Michael Gregoritsch's early opener and a first-half equalizer for Mainz from Jonathan Burkardt.
Freiburg rose into seventh and Mainz left the danger zone on goal difference, with Bochum now third last.
Leverkusen started brightly into their first league match since clinching a maiden title with five games to spare last weekend with a 5-0 demolition of Bremen.
Jeremie Frimpong aimed wide and headed over in the opening minutes, and Alejandro Grimaldo's fired narrowly over from a distance and on a free-kick in the 39th.
Dortmund finally threatened shortly before the break from Marcel Sabitzer's drive which was saved by Lukas Hradecky, and Ian Maatsen failed to capitalise on the rebound.
Dortmund goalkeeper Gregor Kobel had to be alert in the 57th when he tipped Grimaldo's tight-angle free-kick from the right over the bar. Kobel then also bravely kept out Nathan Tella's sliding effort at the far post.
The hosts then drew first blood in the 81st when Füllkrug volleyed home Sabitzer's cross. Hradecky got his gloves on the ball which however went in off the left post.
Tempers flared in the closing stages with Leverkusen's Victor Boniface sent off but the red card rescinded upon review, and the visitors fought on for the deserved late equalizer from Stanisic.
"I just jumped in the air and headed it towards goal. I don't score many goals but this one was really amazing," Stanisic said. "We came here to win. We always give our all and don't give up."
