Former Manchester United manager Sir Alex Ferguson described Kevin Keegan as someone who displayed his passion for football openly while offering a warm tribute to his one-time adversary.

Following the announcement of Keegan's passing at age 75 on Monday, Ferguson looked back on their time as opposing managers and highlighted the significant influence the former Newcastle United boss had on the Tyneside outfit.

"I held him in the highest regard," Ferguson, whose side famously edged out Newcastle for the Premier League crown in 1995-96, told Track Radio.

"We faced off several times during his tenure at Newcastle, yet the work he accomplished there was truly outstanding," he added.

Keegan's initial period leading the Magpies ran from 1992 to 1997. He led the side to promotion into the Premier League in 1992-93 and then saw them finish second behind United three seasons later.

"He revitalized the club and instilled the energy and devotion that dedicated fans provide. That sums up his contribution," Ferguson noted.

"He also recruited three outstanding talents to the squad - David Ginola, Faustino Asprilla and Philippe Albert - bringing added quality, and the contests we encountered with Newcastle during that era were substantial," he continued.

"Kevin showed his deep affection for the game clearly, without doubt, and that enthusiasm extended to supporters and players alike.

"That era at Newcastle was filled with feeling and thrill. They introduced those star players who enhanced the side further, creating what I believe was their finest team ever."

Keegan famously declared "I will love it if we beat them" during a televised moment directed at Ferguson after Newcastle surrendered a 12-point advantage and lost the title race to United in 1996.

The outburst followed Ferguson's comments questioning whether Leeds and Nottingham Forest would compete as fiercely against Newcastle as they would versus Manchester United.

Ferguson remembered encountering Keegan at Wentworth Golf Club weeks after the campaign ended, noting an absence of ill will as they enjoyed each other's company.

"What stood out was his lack of resentment. That was a remarkable trait, and we shared a memorable evening," Ferguson said.

"Whatever had occurred in prior weeks was quickly set aside. I admired him greatly for that quality."

Ferguson added his voice to the many tributes for the former England captain and manager, whose playing days included stints at Scunthorpe United, Liverpool, Hamburg, Southampton and Newcastle.

He secured three league championships, the European Cup, two UEFA Cups and the FA Cup across six seasons from 1971 to 1977 with Liverpool.

Keegan helped Hamburg claim the Bundesliga title and earned consecutive Ballons d'Or in 1978 and 1979, remaining one of just four English recipients of the honor.

In management, he also took charge at Fulham and Manchester City besides his roles with England and Newcastle.

Keegan brought Alan Shearer to Newcastle for a world-record 15 million pounds in 1996 and later managed England while the striker captained the national team.

"He was my friend. A person admired by all. For his passion. For his drive but above all for his companionship. He cherished football and held Newcastle closest to his heart," Shearer said.

"I feel privileged to have known him. We will miss you, Kevin."

Newcastle's present manager Eddie Howe reached out to Keegan upon his own appointment in 2021.

"Kevin inspired me as a young player and, I am proud to say, became a friend whose advice and encouragement proved valuable in recent times," Howe remarked.

"He extended remarkable kindness and openness. Having already contributed so much to this club, he made me feel at home right away.

"Kevin grasped the honor and duty of managing Newcastle United better than most. He freely offered his insights, support and guidance, for which I remain thankful."

Former Scotland and Liverpool forward Sir Kenny Dalglish called Keegan "one of the finest players of his era" who "wore Liverpool's iconic number seven shirt with distinction."

"His on-field accomplishments were remarkable, yet he was also a fine individual and true gentleman," Dalglish added, having been signed from Celtic to succeed Keegan at Liverpool in 1977 before later following him as Newcastle manager.

"He created lasting memories for many and his sides played in a style fans enjoyed watching.

"Football has lost one of its genuine legends."

Phil Thompson portrayed his former England and Liverpool colleague as "the finest person I have encountered in football and sport."

"He was a wonderful man beyond his playing feats," said the ex-defender. "Humility flowed from Kevin."

He continued: "When he arrived at Liverpool, he was a star in the making. We gained a superstar in 1971 and he proved transformative. He motivated everyone."

Former Liverpool attacker David Fairclough debuted for the first team in 1975 and recalled looking up to Keegan while adopting aspects of his approach.

"I remember returning home after training as an apprentice and telling friends how near I had been to Kevin Keegan," Fairclough shared with BBC Radio Merseyside. "I would mention that he had even spoken to me.

"As a youngster, it felt special that he had acknowledged me. My friends were amazed because he was the standout figure at Liverpool then."

Keegan netted 21 goals across 63 appearances for England from 1972 to 1982 and managed the team from February 1999 until October 2000.