Bayern Munich opened their German Cup defence with an unconvincing performance against fifth-division Windeck, though the eventual 4-0 victory was comfortable enough.
Bayern won the domestic Double last season under Louis van Gaal but took until the 43rd minute to take the lead against the minnows when Miroslav Klose converted from a Diego Contento cross.
Franck Ribery added a second just minutes later to ensure Bayern enjoyed a 2-0 lead going into half-time, and Toni Kroos (84) and Mario Gomez (85) put some gloss on the scoreline.
Van Gaal said: "It's always hard to have maximum concentration against a small team, but it's our worst match since the start of pre-season.
"We should also give credit to our opponents, who played very well for 90 minutes. We did what we had to do, that's all."
Schalke, without new signing Raul, looked far from impressive when only beating ten-man Aalen 2-1 in the first round.
Aalen were down to ten men after 18 minutes when Andreas Schoen was dismissed, and Schalke took advantage as Jefferson Farfan scored twice (42, 46).
However, Schalke conceded a late penalty and Tim Bauer scored to set up a nervous conclusion.
Coach Felix Magath said: "You could see today that our attack, without Raul, would not be strong enough to compete in the Bundesliga. In general we still need also to get some reinforcements."