Bayern Munich head coach Pep Guardiola has warned his defenders that they will be punished for not being at their best against Borussia Dortmund forward Pierre-Emerick Aubameyang.

Dortmund will visit the Allianz Arena on Sunday looking to end Bayern's 100% record in the Bundesliga this season, and Guardiola has no doubt about the threat posed by Aubameyang, who has already found the net nine times in the league.

"Aubameyang is incredibly dangerous. He has a lot of quality and is very fast," the Spaniard told reporters. "Our defence will have to remain alert all game.

"It is nearly impossible to keep him quiet when he gets some space."

Bayern and Dortmund are the only two unbeaten sides in the Bundesliga after seven games.