Hansi Flick was unwilling to risk Lucas Hernandez after he complained of an adductor issue while Bayern Munich were 3-0 up at half-time.
Robert Lewandowski scored two as Bayern Munich made it eight straight Bundesliga wins and 14 in their last 15 by beating Fortuna Dusseldorf.
Leroy Sane could join Bayern Munich in their "new era", and Uli Hoeness hopes they can afford Kai Havertz as well.
Hansi Flick tidak mahu pemain Bayern Munich dibuai dengan kemenangan ke atas Borussia Dortmund walaupun kini di landasan terbaik meraih kejuaraan liga.
Bayern Munich look to be cruising towards an eighth straight Bundesliga title, but Hansi Flick is wary they are not yet over the line.
We preview the latest round of Bundesliga matches with the pick of Opta's pre-game numbers.
Robert Lewandowski has terrorised Bundesliga defences for years but has yet to get off the mark against Fortuna Dusseldorf.
Lucien Favre menegaskan bahawa dia tidak akan mengundurkan diri sebagai pengurus Borussia Dortmund meskipun menempa kekalahan "Der Klassiker" kepada Bayern Munich yang tampaknya mampu mengakhiri harapan mereka merebut gelaran Bundesliga.
Borussia Dortmund coach Lucien Favre has not announced he will depart the club "in a few weeks".
Bayern Munich look destined to retain their Bundesliga title after their Klassiker win, but Hansi Flick is not celebrating just yet.