The two Premier Soccer League (PSL) giants are set to lock horns in the Shell Helix Cup on Saturday afternoon at FNB Stadium and they have already started firing blows.
A week ago, ‘Jingles’ pointed the finger at refereeing mistakes Chiefs had benefitted from, and the German coach is not happy with those remarks.
"There's a lot, making a lot of noise, not on your team but making noise on other teams," Middendorp said to SoccerZone on Monday night.
"What does that tell you? It shows that there must be respect and a bit of fear.
"I talk about my players, my team and that's it. I don't need to get into refereeing decisions and other decisions saying "this is not right".
"Sorry why are you doing this? Especially in such a position being the Absa Premiership champions."
Meanwhile, the clash at the majestic venue will be followed by a PSL fixture at Loftus Versfeld Stadium on October 27 but Mosimane wants his men to take the Cup clash seriously.
"A game between Sundowns and Chiefs is never a friendly game. The previous Shell Helix fixture showed that last year," Mosimane responded.
"We're going to be taking it very seriously, it's a serious game.
"And coach (Middendorp) is right, I've made a lot of noise. I thought that they don't hear the noise so I'm glad they got the noise.”
Sundowns are the current holders of the Shell Helix Cup.