The centre-back felt sad seeing his former team-mates suffer a heavy defeat in the Allianz Arena on Saturday, even though he was on the other side
Mats Hummels expressed empathy for former club Borussia Dortmund following Bayern Munich's 6-0 hammering of Peter Stoger's side in Der Klassiker.
A hat-trick from Robert Lewandowski, along with efforts from James Rodriguez, Thomas Muller and Franck Ribery, capped off a memorable win for the Bundesliga leaders at the Allianz Arena.
Hummels, along with the rest of Bayern's defence, was hardly troubled by Dortmund's tame attack, with Mario Gotze's effort against the woodwork the closest Dortmund came to a consolation, and the Germany international felt for his former team-mates.
"There were a lot of ex-colleagues on the pitch today, so of course you feel a bit too," Hummels said.
"I have also lost here [with Dortmund]. I know how much it hurts. But next time it can look quite different again.