"It would be nice to make a difference," McEnroe told CNN as he reflected on his new role as consultant to Raonic for the grass court season.
"If you had told me before when I was just doing commentary, 'Name five or six guys who could possibly win Wimbledon,' Milos [Raonic] would have been one of them."
The last North American man to win the Wimbledon title was Pete Sampras in 2000, but McEnroe predicted the tennis world had yet to see the best of Raonic.
The Canadian looked in fine form at the Queen's Club recently, reaching the final of the pre-Wimbledon event and going one set and 3-0 up against Andy Murray before eventually losing to the Briton.
"Over the next couple of years Milos could get better and 1-2% for a guy like him could scare some people. Anybody," added McEnroe.
The latest in a distinguished line of so-called super-coaches, McEnroe will now be sitting in the stands alongside the likes of Boris Becker -- who works with Djokovic -- and former nemesis Ivan Lendl, who has teamed up again with No. 2 seed Murray.
"Look at Becker and Djokovic," continued three-time Wimbledon champion McEnroe. "If you look at Novak's record since Boris has been there, it's been phenomenal.
"His record against top guys, the amount of majors he's won -- it's been a win-win for both of them, and tennis."
A complex relationship
McEnroe, of course, has history with Becker.
The German prevailed eight times out of 10 in clashes during their playing careers, but McEnroe was then hired to coach Becker at a similar point in the 1993 season.
"The timing may not have been absolutely right... Or maybe he just didn't listen to anything I said because he didn't agree with anything I said!" laughs McEnroe, reflecting on their working relationship.
"Obviously Boris is an incredible champion, and part of the reason he won was because he's stubborn. You believe in yourself.
"So the key is to sort of get in the person's head and make him say 'OK I'm willing to listen.'"
Only it wasn't that quite that simple, and this time that famously abrasive McEnroe ego wasn't necessarily to blame.
"If I said go this way, he'd go that way," McEnroe jokingly recalls. "If I said let's play a tournament, he'd say 'No I think I'm going to get back to Europe for a week.'
"It would certainly be a fun story to share if we ever get a full chance to tell. We can both have a good laugh!"
Old rivalries; new names
In the end, the unlikely arrangement lasted no more than a few months as McEnroe -- who had only recently retired -- dealt with divorce proceedings.
Now they meet again, in altogether different circumstances.
While McEnroe has since displayed his credentials with some panache in the commentary box, Team Djokovic's charge into the history books shows no signs of slowing with Becker at the helm.
Holding all four grand slams, Monday saw Djokovic get his 2016 Wimbledon campaign underway in typical fashion
, breezing past Britain's James Ward in straight sets.
Raonic, for his part, dispatched Pablo Carreno Busta of Spain on Day One, but McEnroe will be all too aware his protege is on course to meet the Serb in the quarterfinals.
The vaunted "Big Four" of men's tennis may well be starting to dissipate, and Raonic may well make good on his potential and fulfill the ambitions of his coach.
Still, the irresistible force of the Raonic serve must first contend with the immovable object: Djokovic's near-inpenetrable defense.
McEnroe, the old name that's new on the block, must contend with Becker once again.