London - Alex Ferguson said he felt "proud to have been a rival, colleague and friend" of Arsene Wenger after the Arsenal manager announced on Friday his intention to step down at the end of the season.
Wenger has been at the helm of the Gunners for 22 years and his first decade in charge of the London club saw him vying for English football supremacy with a Manchester United side under the control of Ferguson.
The Scottish manager retired from his post at Old Trafford in 2013, after more than 26 years in charge and on Friday he paid tribute to his French adversary.
"I am really happy for Arsene Wenger," Ferguson told United's website. "I have great respect for him and for the job he has done at Arsenal.
"It is great testament to his talent, professionalism and determination that he has been able to dedicate 22 years of his life to a job that he loves.
"In an era where football managers sometimes only last one or two seasons, it shows what an achievement it is to serve that length of time at a club the size of Arsenal."
Ferguson added: "I am pleased that he has announced he is leaving at this stage of the season, as he can now have the send-off that he truly deserves.
"He is, without doubt, one of the greatest Premier League managers and I am proud to have been a rival, a colleague and a friend to such a great man."
United's next outing at Old Trafford is against Arsenal in the Premier League on Sunday, April 29.
It will be the 60th time the Frenchman will have faced United, having so far won 18, drawn 15 and lost 26 matches against the Red Devils.