Jefferson Farfan gave Schalke an early lead in the Ruhr derby but Lukasz Piszczek equalised in the 17th minute of a physical, unattractive game which eventually left the visitors with one hand on the championship trophy.

Sebastian Kehl took advantage of poor defending to score the winner in the 63rd minute as champions Dortmund completed the Bundesliga double over Schalke and extended their unbeaten run to 25 games.

Relegation-threatened Hertha Berlin scored three goals, had a player sent off and survived a penalty miss - all in a 15-minute period during a 3-3 draw at Bayer Leverkusen.

Elsewhere, struggling Hamburg SV secured a much-needed 1-0 victory over Hanover 96 while bottom club Kaiserslautern's 2-0 defeat at home to Nuremberg left them all but relegated.

Augsburg boosted their survival hopes with a 2-1 victory at VfL Wolfsburg.

Dortmund, who have three games to play, lead with 72 points from 31 games, nine ahead of Bayern.

Schalke, still on course for a place in next season's Champions League, have 57 points.

Hamburg, the only ever-present team in the Bundesliga since it was founded in 1963, are 14th on 34 points, one ahead of Augsburg.

Cologne, who visit Borussia Moenchengladbach on Sunday (1330), are in the relegation playoff place in 16th position with 29 points while Hertha have 28 and Kaiserslautern 20.

The 140th Ruhr derby began in dramatic style as Peru forward Farfan picked up a loose ball and fired his shot through a crowd of players to give Schalke a ninth-minute lead.

Piszczek replied eight minutes later, the Pole rifling in a left-foot shot from a difficult angle.

After that the match turned into an ugly, confrontational battle with plenty of bad challenges.

Schalke had the most pressure but Dortmund snatched the winner following a corner when the ball hit home defender Christoph Metzelder on the chest and landed at the feet of Kehl to shoot in from close range.

Hapless Hertha looked set for another defeat as Andre Schuerrle and Stefan Kiessling scored either side of halftime to put Leverkusen 2-0 ahead.

That was followed by an amazing spell as Pierre-Michel Lasogga headed one back in the 62nd minute followed four minutes later by a penalty for Leverkusen which also resulted in a red card for Hertha's Levan Kobiashvili.

However, Simon Rolfes saw his spot kick saved by Thomas Kraft, Eren Derdiyok went wide with the rebound and five minutes later, Tunay Torun pulled Leverkusen level.

In the 77th minute Raffael pounced on a dreadful backpass by Tranquillo Barnetta and laid the ball back for Torun to strike again.

But Kiessling spared Leverkusen's blushes by heading his second goal with six minutes to play.