The BVB dominated possession from the kick-off and opened the scoring with 15 minutes gone as Donyell Malen danced through Cologne’s defender before squaring into the path of Raphael Guerreiro, who beat Cologne goalkeeper Marvin Schwabe from tight angle.
Dortmund gained momentum and made it two minutes later when Sebastien Haller hammered home Guerreiro’s assist to flabbergast the visitors.
Cologne showed a sign of life and almost halved the deficit out of the blue but for all that Dortmund custodian Alexander Meyer palmed Dejan Ljubicic’s dangerous attempt to the left post in the 21st minute.
Dortmund remained unimpressed and tripled its lead at the half hour mark as Guerreiro picked up a loose ball inside the box before setting up for Marco Reus, who chipped the ball into the top left corner. Cologne couldn’t hold Dortmund back while the hosts showed no mercy and made it four through Malen in the 36th minute.
Cologne suddenly sparked to life and reduced the arrears against the run of the game as Davie Selke tapped home his own blocked shot from very close range, with three minutes remaining in the first half.
Dortmund’s win was never in danger though as the BVB wasn’t done with the scoring. Haller and Reus both reaped a brace to round off the 6-1 win on home soil.
With the win, Dortmund take over the Bundesliga top spot with a one-point lead for now.
“It is a well-deserved victory for us. The four goals in the first half smoothed the way for all three points. We controlled the ball and created a lot of danger in front of the target. Overall, a great team performance,” said Dortmund skipper Reus.
Elsewhere, Bochum secured their second straight win after stunning third placed Leipzig 1-0.
Andrej Kramaric’s double strike helped relegation-threatened Hoffenheim edge Hertha Berlin 3-1.
Wolfsburg edged Stuttgart 1-0 thanks to Omar Marmoush’s winner and Marius Bulter’s late 1-1 equalizer ensured Schalke a point at Augsburg.
Already on Friday, Borussia Monchengladbach played out a 2-2 stalemate with Werder Bremen.