Mooy shocked fans in Australia as well as those at Brighton and Hove Albion by joining Shanghai SIPG in August.
Duke, whose subsequent move from the Western Sydney Wanderers to Al-Taawoun of Saudi Arabia was also questioned, insists that a move to Asia is more beneficial than many think.
“We don’t have players playing consistently in the top five leagues but Asia is getting much stronger,” Duke told The World Game.
“Look at Aaron Mooy. Some people think he will go backwards in China but he is not going to lose anything, he is still playing against good players. If anything, he will grow.”
Duke believes that the pressures of being a high-profile import in big Asian leagues are underestimated.
“As a foreigner, you are brought to a club to be different, they expect you to be better than the locals and you have to be as you are often paid more.
"You either grab that chance with both hands and make an impact or don’t. It is cutthroat.
"If you don’t perform, you get pushed out quickly. It is a good test. People lost their minds about Mooy’s move to China but it could be life-changing and it could be great for him.
"Some people questioned my move, saying I was going backwards but those comments are bizarre.”
The former Wanderers skipper has already made an impact for his new club.
His late header in the final group game of the AFC Champions League gave Al-Taawoun a 1-0 win over Qatar's Al-Duhail in September and sent the Saudis into the knockout stage for the first time in their history.
He also played against Brad Jones in last weekend’s 1-0 win over Al-Nassr in the Saudi Pro League. He is impressed with the standard.
“Training is a little less intense as you have to preserve your body more," Duke said.
"The games are intense but played at night and the temperature is great.
"There is relegation and games are always a battle and you want to get points on the board to make sure that you get in the top half of the table so you can start thinking about getting into the top three and the Champions League.
“These are early days but so far, so good.”
