Premier League managers pay tribute to Sir Alex Ferguson
"It was a great honour to beat him in Old Trafford and I wish him good luck for his future. I don't know for which reasons [he has retired].
"For me it was fantastic to compete against him in every derby because he was a top manager. I think we should respect his decision.
"Everyone can have his opinion but one manager who stays for 27 years in the same club and won every trophy for 27 years - it is an incredible situation.
"I don't think there will be another manager like him. It is difficult to say Sir Alex is the best but he is the best in the last 27 years.
"I think that when there is a top club like United, you can change the manager, an important manager like Sir Alex who built this team, but I think the club will stay a big club.
"It has a big history. I don't think that will change."