Even if you aren’t a tennis fan, you’re probably familiar with John McEnroe and his arguments with chair umpires. While those clips don’t paint the former United States star in the best light, he did show some remarkably good judgment in 1980.

At the time, John McEnroe could have earned an easy $1 million by agreeing to play Bjorn Borg in South Africa. The young tennis star ultimately passed on the offer, though; in his mind, something bigger than money was at stake.

John McEnroe and Bjorn Borg were two of tennis’ biggest stars

In the world of sports, there’s nothing like a good rivalry. While John McEnroe and Bjorn Borg might not have gone head-to-head for the longest time, they still defined an era of tennis.

Borg rose to prominence before McEnroe, bursting onto the stage as a teenager in the 1972 Davis Cup. He claimed the crown at the 1974 French Open shortly after turning 18; that would usher in an era of incredible dominance, with the Swede winning 11 Grand Slam titles and spending four years as the world’s number one player.

McEnroe arrived on the scene later and proved to be the polar opposite of Borg. While the Swede came across as a stoic ‘Ice Man’, the American was prone to emotional outbursts and verbal sparring matches with officials. That set up a strict dichotomy; you either loved McEnroe or thought he had no place on the tennis court.

That stylistic clash came to a head in 1980, when McEnroe and Borg met in the finals at Wimbledon; the Swede came out on top in an epic, five-set duel. They would face off again at that summer’s US Open. McEnroe got his revenge, though, claiming victory in another five-set final.

A million-dollar match in South Africa

After those two meetings, John McEnroe and Bjorn Borg were tennis’ two biggest stars; fans around the world couldn’t wait for their next meeting. That showdown, however, could have happened sooner than the next major tournament.

As documented by the Washington Post, Borg and McEnroe were supposed to settle the score by playing a five-set match in Bophuthatswana; both men would be paid handsomely, with “the winner was almost sure to gross $1 million and the loser slightly less.” There was a catch, though.

If the name Bophuthatswana doesn’t ring a bell, it was “one of the two phony independent nation-states that have been forced upon unwilling black South Africans in the last seven years by the white-minority government,” the Post explained. “The other phony ministate is Transkei. These noncontiguous, supposedly racially integrated areas are completely dependent upon South Africa. … The object of this “independent” scheme by the South African government is to one day have a country with no black South Africans. The country’s 22 million black citizens are to be stripped of their native-born citizenship and granted new passports from new governments that no one recognizes.”

John McEnroe turned down the $1 million match

As explained in the Washington Post story, Bjorn Borg was prepared to accept the offer; according to his manager, he wasn’t involved in politics and just wanted to play tennis. McEnroe, however, had another idea.

“I remember that it felt wrong,” McEnroe told Graham Bensinger. “So I thought to myself, ‘Yeah, this is an unbelievable amount of money at the time, but there’s a reason why they’re offering me an unbelievable amount of money.’ Because they’re going to take advantage of me and sort of use that propaganda in a way. I mean, I was 21, but I could get that. So I wasn’t going to be the pawn in that whole thing.”

While McEnroe explained that he didn’t feel the decision was a particularly tough one—he was young and would have plenty more time to earn money—people still noticed. Years later, for example, he met Nelson Mandela. “He said it was an honor to meet me,” the former tennis ace explained. “That’s what I should be saying to him.”

During his time on the court, John McEnroe made his fair share of questionable choices. Declining a $1 million offer to play in South Africa, however, was “one of the better decisions” he ever made.