Mats Hummels has heaped praise on his former teammate Robert Lewandowski ahead of the crucial match with Bayern.
Lewandowski followed his record breaking five-goal haul against Wolfsburg with a double against Mainz, taking his BuLi tally to 101 goals in 168 appearances.
The Poland international netted 74 of those goals alongside Hummels when he was with Dortmund, winning back-to-back BuLi titles under Klopp before moving to Bayern.
Hummels admits he still enjoys the display of Lewandowski despite the switch in allegiance.
“I had an incredulous smile on my face when Lewy [Lewandowski] scored his five goals, since I don’t see the shirt or the club for which he plays, just an exceptional striker,” Hummels told Bild am Sonntag .
“You can enjoy his goals, even as part of BVB. He is a complete machine.
“No matter what he does, he doesn’t have to answer to anyone. He did something unpredictable and extraordinary at BVB.”