Berlin, Jan 27 (DPA) Bayern Munich made sure of a place in the semi-finals of the German Cup with a 4-0 drubbing of second-division Alemannia Aachen, but first-division sides Hoffenheim and Kaiserslautern crashed out Wednesday.

Thomas Mueller hit a quick second-half double and substitute Arjen Robben was on also target late on after a first-half goal from Mario Gomez as Bayern stayed on course to defend their cup title.

Aachen had twice eliminated Bayern in the cup - in 1994 and 1996 - but Gomez's headed goal in the 26th minute and Mueller's brace in the 75th and 80th followed by a fourth from Robben two minutes from time made it an ultimately comfortable evening for Louis van Gaal's side at the Tivoli ground.

Bayern, with Philipp Lahm as new captain succeeding the departed Mark van Bommel, will be joined in Sunday's draw by second-division outfits MSV Duisburg and Energie Cottbus after upset victories.

The semis are completed by Schalke 04 who were 3-2 extra-time winners over Nuremberg Tuesday.

Van Gaal saw Gomez net his 24th goal in all games this season, heading in a cross from the left from new 17-million-euro ($23.3 million) signing Luiz Gustavo, playing as left-back, and could easily have scored two more before the break.

"He took the first chance which I think is better than the third or fourth. It was a good pass from Luiz Gustavo and he took it well," Van Gaal said.

Duisburg, third in the second division, dumped Kaiserslautern out with a 2-0 victory while Cottbus shocked Hoffenheim with a late goal for a 1-0 win to continue a run of victories over first-division sides following the elimination of Freiburg and Wolfsburg.

Dutch striker Ryan Babel's debut for Hoffenheim following his move this week from Liverpool was spoiled by an 84th-minute winner by Chinese midfielder Jiayi Shao at Cottbus who reach the last four for the second time since 1997.

Duisburg overcame Kaiserslautern thanks to goals in each half from Branimir Bajic and Goran Sukalo in the club's best cup run for 13 years when they also reached the semis.

The home side went in front in the 36th minute when keeper Tobias Sippel miscued an attempted punched clearance from a corner and the ball was headed on to Bosnian defender Bajic who netted from close range.

Slovenia midfielder Sukalo then headed a second in the 58th from a free-kick to ensure another giant-killing act for the Zebras who eliminated Cologne in the previous round.

"We didn't play with any passion and fully deserve to go out. Duisburg were better than us in every area of the game," Kaiserslautern coach Marco Kurz said.