So when McDermott says that the effect Rafa Benítez has had on Newcastle is like that of Keegan in the 1990s, you sit up and take notice.
Keegan took over a United side struggling to avoid relegation to the third tier of the Football League for first time, playing at a dilapidated St. James' Park, and turned them into the most thrilling side in the country.
When Benítez replaced Steve McClaren in March 2016, Newcastle were on their way to the Championship, but the Spanish manager was able to unite the fanbase, galvanise the players and revive the club as he led them straight back to the top flight.
Their footballing philosophies may be a little different, but the impact both men have had on Tyneside has been remarkably similar - and that isn't lost on McDermott, who was back in the North East for the 125 Plate event at Newcastle Racecourse last week.
"He's a top manager, isn't he?", said McDermott, who had two spells at St. James' Park as a player before a long association with the club as a coach, on Benítez.
"He's not just any manager; Jose (Mourinho) keeps saying he's the 'special one', but I think Rafa is the 'great one', because he has been a great over the years. I just hope he's going to be here for the long haul."
When asked by NUFC TV if Benítez's Rafalution was comparable to to the upturn in United's fortunes under Keegan, McDermott answered: "Yeah, definitely.
"He sets up teams not to lose; Kevin never did that, Kevin wanted to put a team out that won every game. It was inevitable that they would concede, but they didn't half entertain in those years.
"Let's hope the Newcastle of the '90s can be replicated now. It's not going to be easy to follow those players, but we live in hope."
The 125 Plate event was attended by a whole host of former Newcastle United stars as the club continues to celebrate its 125th anniversary season.
And McDermott - who won 25 caps for England and was the PFA Players' Player of the Year for 1979/80 - said: "It's been brilliant seeing all the ex-players - Jimmy Smith, Malcolm Macdonald, Jackie Charlton, Mick Martin. It's a fantastic occasion and rightly so for a great club.
"It's great talking to the lads about games and it's nice to be with some people that you haven't seen for a long time. We're all getting older, we're all changing - I'm the only one one who hasn't really changed, I've been told!
"'Jinky' Smith looks better now than when he was about 30 and Mick Martin hasn't changed because he looked like that when he was three!
"It's great to see them and great to be part of it. It's a great club. I'm one of the lucky ones; I played for a great club with great, great supporters."
