Borussia Dortmund plunged to new depths as they were humiliated 5-1 at home by promoted VfB Stuttgart - a result that under-pressure manager Lucien Favre admitted was a "catastrophe".
Giovanni Reyna equalised for the home side against the run of play after Silas Wamangituka's penalty with the score locked at 1-1 going into the interval.
The Congolese striker Wamangituka then quickly restored the lead after the break with his second before Philipp Foerster, Tanguy Coulibaly and Nicolas Gonzalez took advantage of poor defending.
It matched Dortmund's record home defeat - the hosts' third in succession at their own stadium - leaving Favre under huge pressure after just one win in five domestically.
The result leaves Dortmund fifth, five points behind leaders Leipzig.
"It was a catastrophe ... too many big, big mistakes," conceded Favre. "We were very, very bad. It's unacceptable."
Leipzig's sensational form continued with first-half goals from Marcel Sabitzer, from the penalty spot, and Dani Olmo taking them top, at least until champions Bayern Munich visit Union Berlin later on Saturday.
Leipzig were gifted the lead when Ludwig Augustinsson elbowed Yussuf Poulsen in the box, allowing Sabitzer to convert the 27th-minute penalty.
"You can give the penalty for that," said Bremen coach Florian Kohlfeldt, who had protested on the pitch. "I apologise to the referee."
A clever flick from Poulsen and quick thinking from Olmo to beat his man doubled the lead before the break.
Cologne continued their revival with Elvis Rexhbecaj scoring their winner in the 1-0 win at second-last Mainz while Freiburg did likewise 2-0 at home to Arminia Bielefeld.
Hertha Berlin drew 1-1 at Borussia Monchengladbach.