Borussia Dortmund kept their bid for European qualification alive as they completed a club record seventh straight win with a commanding victory over Karlsruhe.
Jakub Blaszczykowski opened the scoring in the 25th minute before Nuri Sahin, Felipe Santana and Alexander Frei wrapped up the points in the final half-an-hour.
Dortmund are now level with Hamburg in fifth - the final Europa League qualifying place - although Martin Jol's side can move clear with victory over Werder Bremen tomorrow.
Defeat for Karlsruhe, though, pushed the basement boys a step closer to relegation, leaving them four points from safety.
Both teams started aggressively but the hosts soon began to take control of the game after 10 minutes and took the lead after 25 minutes.
Frei was the provider, playing a ball over the Karlsruhe defence down the right where Blaszczykowski unleashed a beautiful drive which went in at the near post.
Karlsruhe nearly equalised five minutes before the break. Sebastian Kehl's attempted clearance went to Joshua Kennedy, who beat Felipe Santana and Dortmund keeper Roman Weidenfeller only to see his shot strike the left-hand post.
The hosts could have been out of sight shortly after but contrived to miss a host of chances through Nelson Valdez, Felipe Santana and Kehl.
Those misses would not prove costly, though, as Sahin doubled the lead in the 62nd minute with a fine left-footed free-kick from 22 yards which found the right corner.
Felipe Santana headed the third from a corner with 19 minutes to go and Frei made it four 10 minutes from time.
The Switzerland striker was sent clear by a throughball from Kevin-Prince Boateng and beat Karlsruhe keeper Markus Miller from 11 yards.