Manchester City manager Roberto Mancini has said he considers Manchester United counterpart Sir Alex Ferguson a "teacher" as he prepares for Sunday's derby match.
The top two in the Premier League face each other at Old Trafford, with Mancini seeking a first league victory over Ferguson's side.
"I can say thank you to him because I have big respect for him - he won everything for 25 years," Mancini said.
"He is a teacher and I learn from him."
The Italian believes all aspiring managers should look up to Ferguson.