Borussia Dortmund coach Jurgen Klopp has refused to get carried away with his side's impressive performance in the Champions League so far this season.
The German champions defeated Manchester City 1-0 at home on Tuesday to finish Group D with 14 points, three points ahead of second-placed Real Madrid.
"We are happy with the way things have gone for us so far this Champions League season but we know that it's an incredibly tough competition," he said.
"Milan, Porto or Juventus are potential opponents in the next stage, but we have surely gained some respect with our performances in the group stages.
"We will just have to wait and see what's in store for us. It's been a great experience so far."
The draw for the last 16 will be made on December 20.
