Sir Alex Ferguson will go down in history as one of the greatest managers of all time.
The legendary Manchester United boss stepped down in 2013 after 26 years at Old Trafford, in which time he won 38 trophies.
Ferguson was appointed as Ron Atkinson's replacement in November 1986, with the Reds languishing second from bottom.
He won his 13th Premier League title during his final year in charge.
Led by innovative French manager Arsene Wenger, Arsenal were the first team to launch a sustained challenge to United's dominance.
"Over the years we enjoyed some fantastic battles and you could say we had survived together and respected each other's efforts to play good football," said Ferguson in 2014.
"I always enjoy watching Arsène's sides – Arsenal play the right way.
Fergie's pre-Arsenal team talk
Channel 5 screened 'The Feud' on Monday night - a documentary focusing on the rivalry between Ferguson and Wenger.
A brilliant clip of Ferguson talking to the players ahead of a game against Arsenal has been shared on social media.
"Don't f***ing attempt to let him f***ing bully you," he tells the United players in a tactical meeting.
"I don't care if you do it verbally or physically, you just f***ing make sure you're ready for him."
Watch the full clip below.
He didn't hold back with the swear words.
“Fergie was scary and even now he still scares me” said Giggs in 2016, as per The Mirror.
“I still call him boss because he just has that aura about him. He had that little cough and as soon as you heard that, walking down the corridor at the training ground, you’d dive in a doorway to get out of his way.
“I was always wary of him because he had that ability to turn up at your house – and he sometimes did."
Wenger last week announced that he would be leaving Arsenal at the end of the 2017/18 season - and his former adversary paid a wonderful tribute.
"I am really happy for Arsene Wenger," Sir Alex told ManUtd.com. "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.
"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."