The 24-year-old has hit out at the Azzurri after Friday's 1-1 draw, claiming the actions of the likes of the Paris Saint-Germain midfielder are what he has come to expect
Mats Hummels opened the scoring for the visitors in the eighth minute before Ignazio Abate levelled the score 20 minutes later to prolong the Azzurri's unbeaten run against the Germans.
The match boiled over in the closing minutes as Toni Kroos remonstrated with Motta for what he perceived to be over-aggressive challenges, only for the Paris Saint-Germain midfielder to square up to the Bayern Munich man, with both handed bookings.
Muller was left far from impressed with the antics of Cesare Prandelli's men, but claimed he was not surprised to see their physical approach.
"The Italians played like we knew they would – lots of little unfair things," he told reporters.
"I don't know if these belong in a match.
"The referee joined in their play. It is okay to be hard in the duels, but Motta behaved like we know he does and grabs Toni [Kroos'] face."
Kroos echoed the statements of his Bayern team-mate, branding Motta's actions as "assault."
"Both teams wanted to win. It was not too hard. We know the way Italy plays and we were up for it," he said.
"These tests are very good. You can learn where your room for improvement is.
"The first half was very good, we made the ball run. The second half was not so good. It was a good test."
On Motta, he added: "I guess that's what you call an assault."
Germany coach Joachim Low admitted he was not expecting a "friendly" encounter in Milan but insisted he was pleased with how his side performed against a tactically-astute side.
"I am satisfied with how the match went. We showed a good defensive performance and great fighting performance," he said.
"It was clear that we would not get a 'friendly' in Italy. We knew that.
"Months ago we decided to play Italy and England. We wanted to test how good we are. Italy are very good tactically.
"They switch numerous systems during a match and for an opponent it can be difficult to cope with that. And for that, these matches are good."
Germany will travel to London to take on England at Wembley on Tuesday in their next encounter.