Borg -- who will be portrayed by newcomer Sverrir Gudnason -- sparked such a new level of excitement on and off the courts that he was dubbed "the rock star of tennis." Women wanted to be with him; men wanted to be him.
But in 1981, it all started to go wrong.
McEnroe ended Borg's unbeaten five-year run on London's hallowed grass courts in another classic final. When he defeated him again in the U.S. Open final two months later, the former world No. 1 skipped the press conference and fled Flushing Meadows.
Borg would make only a handful of appearances before announcing his retirement in early 1983. He was just 26.
His burnout and anguish ran so deep that he was unable to return to the All England Club for 19 years. Known for his stony on-court demeanor, many wrongly assumed that the game meant nothing to him.
But, as the tennis icon told CNN Open Court's Pat Cash
in a rare interview, the truth was quite the opposite.
"It was like a holy ground for me," Borg says. "I mean, I could not come back. It was not like I disliked Wimbledon -- it was my favorite tournament. They asked me for many years ... I said no, because I wasn't ready to go back."
When Borg did finally return to Wimbledon for the Champions Parade in 2000, a rapt crowd watched as he fell to his knees and kissed the pristinely-kept grass.
"I took that first step. That's why I kissed the grass, because I loved those courts."
The way Borg speaks about it, it's almost like an injured war veteran returning to battlefield. There's great fondness, but a wise respect for what's good for you.
"It came to a point when I didn't care if I was winning or losing -- and if you get to that situation then something is seriously wrong," he told Open Court in 2011 about his retirement
Tennis is a sport where champions often retire young -- Justine Henin and Kim Clijsters being just two recent examples -- but none were as dominant as Borg.
The best match of all time?
Though those days are long behind him, there are certain moments the tennis legend will never forget.
"People come up and say, do you remember the final in 1980? Of course I remember the final. When I speak to John, sometimes we get together ... the thing is, we both remember every single point. We talk about the final -- we know exactly. It meant a lot to both of us."
Their rivalry captured the public's imagination, but in reality their relationship is rooted far deeper in friendship than in hate.
"We respect each other. I respect John, he respects me. It's not too many guys who respect on the tennis court, but I know he respects me because in the beginning when we started to play our first three or four matches, he felt like I was not the bad guy.
"It was more like I wanted to help him in certain ways, because in certain ways he misbehaved or didn't know what to do. That wasn't really his fault -- he was coming into tennis and he was this guy ..."
McEnroe was just 19 when he joined the tour, while Borg was a slightly older and wiser 22, surrounded by adoring girls.
"I thought he was learning a lot of positive things and he felt that I wanted to help him with those things," Borg says. "So I think that's why he respected me, not as a player but even as a person."
They are touching words for a man who stole his Wimbledon crown and inadvertently sparked the end of his career. But after an extraordinary journey soaring into the limelight and out again, Borg seems finally at peace. And it's allowed him to love tennis again.
"We built something in tennis in a positive way. That I was part of that, I am very happy about that. We lifted tennis on a different level," Borg says of the duo's legacy.
"Today it's hitting the ball so much harder, it's a different game. I follow tennis 110% -- I have been watching every single match. Federer, Djokovic, Nadal, Murray ... I love the way they play."
Borg at 60
The "Ice Man" today couldn't seem happier. Laid-back and smiling in a sunlit Stockholm hotel, he could be an advert for the healthy Scandinavian lifestyle.
He's just turned 60, but still has the tanned skin, full hair and lean physique of the steely young man who once drove legions of fangirls (and boys) wild.
Borg enjoys a quiet lifestyle on the outskirts of Stockholm with his third wife Patricia Ostfeldt, visiting the office of his clothing brand three times a week and even doing the school run with his 13-year-old son Leo.
He appears so content, there's little question of regrets over his bold exit from tennis all those years ago. However, there are two small niggles.
"I wish I'd won the U.S. Open. I was in the final four times and maybe two of those finals I should have won," he says, referring to his fighting performances against Jimmy Connors in 1976 and McEnroe in 1980. "But I would never change any Wimbledon for a U.S. Open."
His other remorse is not winning the Australian Open, in part due to its former December scheduling. "I was not really ready to play well on the grass court."
Ahead of his Wimbledon breakthrough in 1976, Borg says his initial practice on the grass that year was "terrible, I didn't hit one ball into the court."
Having trained heavily for two weeks, by the third round Borg was playing "my best tennis" -- he went on to beat American Connors to the title in straight sets. It was his first of three consecutive years of French Open and Wimbledon victories, a feat achieved by no other player in history. How did he do it?
"I think it was very, very difficult," he says with a smile.
"Wimbledon always meant something special to me. I mean it's always been a tournament that most players -- maybe every player in the world -- has a dream about.
"When you walk into those gates, it's mystic. I always have good memories, positive vibes about Wimbledon. I love that tournament."
While McEnroe has maintained his status at SW19 as a commentator and now coach of rising star Milos Raonic
-- who plays Roger Federer on Centre Court in Friday's opening men's semifinal -- Borg is happy to take his place in the stands.
"I'm looking forward to coming to watch the tennis. I think it's going to be a great tournament."