On June 8, 1969, the soccer teams of El Salvador and Honduras met in the first leg of a two-legged qualifier for the next World Cup. The match took place in the shadow of growing tensions between the neighbors; after Honduras won 1-0 in the capital Tegucigalpa, El Salvador fans set fire to the stadium.

A week later, El Salvador won the return match, held in the capital, San Salvador, 3-0. The previous evening, Salvadoran fans had rioted outside the hotel where the Honduran team was staying, resulting in several deaths. On the night of the match, the Salvadorans hung a sullied rag in place of the Honduran flag at the stadium.

Anti-Salvadoran riots broke out in Honduras as a result of the match, and on June 26, El Salvador severed diplomatic relations, claiming that 12,000 Salvadorans had been forced to leave Honduras following the match.

The situation became increasingly tense as the two countries engaged in border skirmishes in the following weeks until war broke out on July 14.

The conflict did not last long: it ended after just a few days following a ceasefire negotiated by the Organization of American States.

Still, when it comes to sports rivalries, the “Football War” (or Soccer War, if you prefer) is a prime example: two nations that were already at odds with each other were drawn into a sports conflict and it escalated into a real conflict.

There is no shortage of sporting rivalries between nations that are at least partly driven by broader geopolitical factors, historical grievances or generations of war.

Sure, the 1980 “Miracle on Ice” is still celebrated in the United States in part because a mostly amateur hockey team defeated the professional powerhouse Soviet Union, but the incident really resonated most for its context: It occurred at the height of the Icy War, when the U.S. administration was considering boycotting the Summer Olympics in Moscow over the Soviet invasion of Afghanistan.

If you want a true taste of newfangled sports rivalry, how about a cricket match between India and Pakistan, two nations that hate each other with the heat of a thousand suns? Or any sporting event between Kosovo and Serbia, Armenia and Azerbaijan, or, someday in the future, when and if current hostilities cease, Russia and Ukraine.

In that context, the much-hyped Mexico-Puerto Rico boxing rivalry, the latest chapter of which will be played out on September 14 between Canelo Alvarez and Edgar Berlanga, is a different story entirely.

There is no particular animosity between the two nations, no history of conflict, colonialism, or conquest. As has been widely noted, Mexicans and Puerto Ricans are more likely to root for each other against a team or athlete from the United States. But inside the squared circle, it has become the ultimate rivalry, the epitome of boxing competition, not least because both Mexico and Puerto Rico have a history of producing exhilarating, high-quality boxers. The rivalry may have no geopolitical or historical basis, but it has become a source of pride for both sides and has led to many memorable fights.

But a national sports rivalry doesn’t have to be fueled by generations of resentment or the threat of future war to be electrifying. Consider, for example, the following, all of which are among the best the rivalry has ever produced:

Sixto Escobar KO9 Rodolfo Casanova

Decades before the Mexico-Puerto Rico rivalry was officially called, Puerto Rican Escobar had wrested the bantamweight world title from Mexican Casanova on neutral territory in Montreal. In a thrilling fight, Escobar knocked Casanova down in the third round, and although the Mexican managed to regain his balance, Escobar scored an uppercut in the ninth round to become the island’s first world champion.

Salvador Sanchez KO8 Wilfredo Gomez

There had been a number of notable clashes between Mexican and Puerto Rican boxers leading up to the 1981 featherweight title fight (Sanchez himself had defeated Juan Laporte the year before, and Gomez had defeated Carlos Zarate in 1978, to name a few), but there’s no denying that this event truly kicked off the rivalry as we know it today.

Both men were already huge stars in their homelands when Don King put them together at Caesars Palace in “The Battle of the Little Giants.” Fans, promoters and television executives noticed the lively, clamorous crowds and the tense atmosphere at ringside and vowed to leverage the Latin—and especially Mexican and Puerto Rican—fan bases to greater ends. In the fight itself, Sanchez defeated Gomez by eighth-round technical knockout, handing the Puerto Rican his first defeat and retaining his crown.

Wilfredo Gomez KO14 Lupe Pintor

Gomez got his revenge of sorts the following year, defending his 122-pound title. In a mesmerizing, brutal fight, he and Pintor traded power, with Gomez doing most of the damage in the first half of the fight and Pintor calmly fighting his way back into contention. In round 14, Gomez seemed exhausted, with one eye closed, until a left-to-the-body/right-over-the-top combination suddenly dropped Pintor for the first time in the fight. Pintor won, but Gomez knocked him down again, and the referee stepped in to stop the great fight.

Julio Cesar Chavez by TKO11 Edwin Rosario

If Sanchez and Gomez lit the match, Chavez and Rosario added fuel to the fire.

“Puerto Ricans talk too much,” Chavez said earlier. “They’re always bragging, they’re always saying, ‘I’m going to crush you, I’m going to knock you out,’ but then they can’t back it up. Rosario has a massive mouth, and the people around him have massive mouths.”

“I’ll send you back to Mexico in a box, you coward!” Rosario snapped in response.

Unfortunately for Rosario and Puerto Rico, this lightweight title fight for Rosario was arguably Chavez’s finest moment, as he broke Rosario, battered him and stopped him in the 11th round.t.

Felix Trinidad TKO4 Yory Boy Campas

Both men were unbeaten – Campas 56-0, Trinidad 23-0 – when they met at the MGM Grand in Las Vegas for Trinidad’s welterweight title. In the second round, Campas’ left hook knocked Trinidad down by the seat of his pants, and when he was hurt again in the third, Trinidad landed a low blow – twice – that earned a reprimand and a point deduction. A seemingly furious Trinidad dominated the rest of the round, then stopped Campas in the fourth with a furious flurry of punches.

Jorge Arce TKO 12 Wilfredo Vasquez Jr

With a record of 56-6-2, Arce was seven years removed from the pinnacle of world championship glory, but he managed to put in another great performance against the younger Vasquez, son of Puerto Rican legend Wilfredo Vasquez Sr. A fourth-round knockdown – the first of Arce’s career – suggested that luck was on the youngster’s side, but Arce refused to be deterred and called on years of experience and determination to outwork and outwork Vasquez, eventually knocking him out before the Puerto Rican’s corner threw in the towel.

Antonio Margaret TKO11 Michael Cotto

Miguel Cotto by TKO 9 Antonio Margarito

When it comes to the level of pure malice, few rivalries involving members of any nationality can match this one. Cotto was undefeated and in the best shape of his life when he faced Margarito in Las Vegas in 2008; and he started off sturdy, boxing beautifully and building a lead on the scorecards until Margarito’s relentless pressure took over, took the fight away from Cotto and caused him to surrender in the 11th round.t.

One fight later, Margarito was knocked out by Shane Mosley and engaged in a dispute over illegal hand wraps, leaving Cotto furiously believing that his defeat to the Mexican was achieved through nefarious means.

When they met in a rematch at Madison Square Garden three years later, Margarito’s right eye had been damaged by Manny Pacquiao’s fists; Cotto relentlessly targeted the same eye and forced the doctor to stop the fight between the eighth and ninth rounds. The gathered Puerto Rican fans celebrated wildly, both inside and outside the renowned arena.

Whether Saul Alvarez and Edgar Berlanga can put on a performance that matches or even comes close to those above, or any other great fight between their countrymen, remains to be seen. However, fans of both sides and neutrals alike will be hoping that this will at least be competitive and engaging, and provide further evidence that national boxing rivalries do not need the threat of pushing two countries into war to be worthy of recognition and celebration.