Berlin, Feb 11- Bayern Munich suffered a minor scare in the quarter-finals of the German Cup football against second-division side Greuther Fuerth Wednesday before eventually cruising to a 6-2 win, thanks to a brace from Thomas Mueller.

Second-half goals from Franck Ribery and Philipp Lahm also helped Bayern to a victory that at times looked far from certain.

Cologne weren't so lucky away to high-flying second division club Augsburg, losing 2-0 courtesy of a third-minute goal from Michael Thurk and a late strike from Raphael, and also finishing the game with eight men.

Adil Chihi saw a straight red card for an elbow after 30 minutes, substitute Lukas Podolski on 69 for a second bookable offence despite the Germany striker only being on the pitch for nine minutes, and Petit also picked up a second yellow card for moaning to the referee five minutes from time.

"That shouldn't happen with a team made up of so many experienced players," said Cologne coach Zvonimir Soldo of the three sending offs.

In the other quarter-final clash of the night, Schalke 04 struggled for long periods against third-division side VfL Osnabrueck before a second-half Kevin Kuranyi effort ensured a 1-0 win.

Fuerth travelled as huge underdogs to the Allianz Arena in Munich and everything appeared to be going to plan for Louis van Gaal's side when the Bundesliga giants went ahead after just five minutes through a clinical Mueller finish.

However, within five minutes Fuerth were level through Christopher Noethe and the visitors should have gone in front on the half-hour mark but Sami Allagui fired wide with the goal gaping.

Allagui made amends for his earlier miss on 40 minutes, heading in a Nicolai Mueller cross to make it 2-1.

Bayern refused to panic and also had luck on their side in snowy conditions when referee Michael Weiner awarded a penalty on 58 minutes after a Robben shot hit falling Fuerth defender Stephan Fuerstner on the arm.

Robben stepped up to strike home the resultant spot-kick although goalkeeper Stephan Loboue will feel he should have saved the Dutchman's weak effort.

Bayern found themselves in front two minutes later when Loboue inexplicably raced from his line only to be side-stepped by Ribery, who then curled the ball into the bottom righthand corner.

Ribery then set up Lahm on 64 minutes for the German defender to make it 4-2 and put the tie past Fuerth.

Mueller netted his second goal of the night eight minutes from time, latching onto a Robben pass before beating Loboue with ease, while Fuerth's misery was completed late on when Allagui headed into his own net.

"We had to step it up after such a poor first half," said Mueller. "We showed another side to ourselves in the second half.

Van Gaal, meanwhile, paid respect to his lower league opposition.

"I think Greuther Fuerth were much more aggressive in the first half," he said. "It is nice that we are still in this competition."

On Tuesday, cup holders Werder Bremen booked their place in the last four with a 2-1 victory over Hoffenheim. (dpa)