Leipzig are a point behind Bayern thanks to goals from Emil Forsberg, Angelino, Marcel Halstenberg, Timo Werner and Marcel Sabitzer.

"We didn't expect such an easy game," Sabitzer, who scored in the very first minute.

"We played really well, we have to praise the team, it has been a tough week."

Haaland took his tally to nine goals in six league games since joining from Salzburg, sealing the win in the 66th for Dortmund to stay four points behind Bayern.

Fourth-placed Borussia Moenchengladbach were on course to stay level with Dortmund in the standings until Lucas Ribeiro scored in stoppage time on his debut to grab a 1-1 draw for visiting Hoffenheim.

Dortmund had to wait until the 52nd before finding the breakthrough at second bottom Bremen.

It came from an unlikely source, as defender Dan-Axel Zagadou scored after being set up by Jadon Sancho following a corner.

Haaland, 19, got his goal when he blasted inside the near post after Achraf Hakimi picked out his run.

The 19-year-old Haaland has netted 12 times in just eight games for Dortmund in all competitions.

Hertha Berlin were routed at home by Cologne 5-0, deepening the sense of crisis at the club in its second game since Jurgen Klinsmann abruptly resigned as coach.

Nothing went the hosts' way as they slumped to a third loss in four games and heaviest of the season.

Fortuna Dusseldorf boosted their chances of survival by beating Freiburg 2-0 to sit six points behind Hertha.

Hertha started ambitiously but forgot about defending, with Jhon Cordoba and Florian Kainz both scoring twice for Cologne before Mark Uth rounded out the scoring with a brilliant free kick.

"Totally unexpected. We had a good week in training," Hertha interim coach Alexander Nouri said.

"It's extremely bitter. We have to apologise to the fans."

Australian Associated Press