Hueng-Min Son scored the only goal as Bayer Leverkusen closed the gap at the top of the Bundesliga with a 1-0 win over Borussia Dortmund as both sides finished with 10 men in a feisty encounter at the Westfalenstadion.
Dortmund were far from their cohesive best as the visitors kept it tight, restricting the hosts to half-chances until the match finally opened out when Leverkusen defender Emir Spahic saw red for a two-footed lunge with 10 minutes remaining.
But the hosts could not make their numerical advantage count with substitute Marco Reus going the closest before Sokratis Papastathopoulos picked up a second yellow card in injury time to compound a miserable evening for Jurgen Klopp’s men.
Both sides came into the match knowing that anything other than victory would allow Bayern Munich to start dreaming of Bundesliga glory.
After a lively opening, Dortmund carved out the first opening when Papastathopoulos flicked on towards Friedrich whose header landed on the roof of the net.
But it was Leverkusen who edged ahead when Gonzalo Castro capitalised on a mistake from Friedrich and threaded through to Son, who rounded the keeper and tucked home.
Lewandowski almost levelled on the half hour when he expertly swivelled to divert a wayward cross on target but it was one of few first-half chances for Dortmund.
And it was Leverkusen who almost scored before the break as they twice went close. First Weidenfeller stood tall to tip Son’s effort around the post and then Jens Hegeler tried to float the ball over the Dortmund keeper only to see his shot drift narrowly over.
The second half was a scrappy affair with a flurry of yellow cards and substitutions breaking up the match’s flow, allowing Leverkusen to edge comfortably towards a massive three points in a period devoid of chances.
But Spahic’s challenge on 80 minutes was adjudged to be reckless, causing him to receive his marching orders and hand Dortmund a glimmer of hope.
The hosts charged forward in an attempt to restore parity but, aside from Reus’ scuffed effort, they could not create a clear chance with Papastathopoulos capping a woeful performance with his second yellow card for petulantly throwing the ball away.
That left Leverkusen to secure a vital three points that keeps them in the Bundesliga title race, while Jurgen Klopp's Dortmund will need a minor miracle if they are to haul in Bayern before the end of the season.