When Ivan Lendl and John McEnroe met in the Wimbledon semi-finals in 1983 they could not have imagined that 33 years later they would be on opposite sides of the Centre Court net once more.
This time one of the sport's greatest rivalries is by proxy, with Lendl's charge Andy Murray taking on Milos Raonic, who McEnroe has been advising throughout the grass-court season, in Sunday's final.
All parties have been keen to stress the sideshow is of no relevance or interest to them, but it certainly adds an extra dynamic to what is already a fascinating contest.
Both men have spent only four weeks with their players and, in McEnroe's case, he is supporting Raonic's permanent coaching team of Carlos Moya and Riccardo Piatti.
But their influence has been hailed by Murray and Raonic, both of whom will hope their super coach can give them the winning edge.
Part of what makes it a fascinating dynamic is that Lendl and McEnroe are such different characters and have brought opposite benefits to Murray and Raonic.
Murray, a highly emotional man like McEnroe, is a calmer, more positive player with the presence of 'Old Stoneface' Lendl in his box.
The Czech-American guided the Scot to his two slam titles at the US Open in 2012 and Wimbledon the following year and rejoined his team this summer after a break of more than two years.
Other players, including his semi-final opponent Tomas Berdych, had tried to tempt Lendl back on tour in the interim and it has given Murray confidence that it was he who managed it.
"I don't think he'd be doing this job if he didn't believe in me and believe that I could win these events, because he doesn't need to," Murray said of the eight-time grand slam champion.
"That helps. But also the information I get from him, the psychological help that I get from having him around, being able to chat to him at these events, before the big matches, makes a difference.
"That's why I think we've been a good team. I think we both trust each other."
By contrast, Raonic is a cool, confident character and McEnroe has worked on getting the 25-year-old to show more emotion and energy on court.
It has certainly helped him this fortnight. He came back from two sets to love down to win a match for the first time in his career against David Goffin in the fourth round and then turned things around against Roger Federer in the semi-finals when the Swiss looked poised for victory.
"I think it's something that we've all been working together at," Raonic said. "I think he's definitely put an emphasis on it.
"A lot of times I felt in matches that I needed to calm myself down to stop things from getting out of control.
"He sort of implemented it in the sense of, 'You tend to be too calm, try to get energy out of you, try to get it out of you on court and leave it all out there'. I think it's more of a positive attitude."
McEnroe had long been talked about as a potential coach for Murray, given their similarities and the American's admiration for the Scot.
But he now finds himself trying to engineer a ninth grand slam final defeat for the British number one.
One thing Murray and Raonic do share is an obsession to wring every last drop out of their talent and McEnr oe, who is likely to be in the commentary box rather than the player box on Sunday, has clearly been highly impressed by the Canadian.
He said on the BBC: "Murray is playing better than he ever has and has more confidence; adding Lendl has added a touch more belief.
"At the same time, that's where Milos is in his career. He's waited for this opportunity for a long time, there's a lot of expectations.
"He's one of the few guys that has admitted, 'I want to be the best in the world, I want to win majors'. Guess what? That puts pressure on you and it's been tough for a while but here he is."
The winner of that 1983 contest? McEnroe.
Source: PA
