Here we go again. Less than a year after Argentina’s Superclasico rivals River Plate and Boca Juniors brought the world of football to a standstill with their thrilling, scandalous first Copa Libertadores final, the pair meet again in the South American competition.They may be clashing this time round in the semi-final stage rather than the decider, but that will make no dent in the famously fervent passion on display from both sets of fans over two legs in October. Indeed, the shocking events of 2018 mean the upcoming tie could be the keenest-fought yet.In one sense, the 2018 Copa Libertadores still remains open. On November 25, the day after their team coach was ambushed by bottle and stone-wielding River fans just a few blocks from the Monumental Stadium ahead of the second leg, Boca made an official complaint first to CONMEBOL and later the Court of Arbitration for Sport. Article continues below Editors’ Picks Ox-rated! 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But it is nevertheless still pending, with Boca holding out, perhaps unlikely, hope that their rivals’ trophy could yet be stripped from them by the end of the year.“We will take this until the end,” Boca president Daniel Angelici vowed upon filing the writ and so far he has proved true to his word, doggedly pursuing the legal battle for the best part of 12 months.All of which means, of course, that there is no love lost between the two Buenos Aires giants. But then there has never been much to spare over the course of a century-old rivalry that began in the grimy docks of La Boca and accompanied each side as they grew to national and continental predominance. That mutual enmity has never been better shown than on the occasions they have locked horns in the Libertadores.Back in 2004, the last semi-final match between Boca and River, a young Carlos Tevez was in the eye of the storm. The 20-year-old striker swooped in the second leg with an 88th minute goal and was promptly sent off for mocking the seething Monumental with his ‘chicken dance’ that almost sparked a riot. River immediately responded against the 10-man Xeneize to send the game to penalties, where Maxi Lopez missed the decisive kick to send the visitors through.Not until 2015 would the two sides meet again in the Copa, in another tie that made the headlines for all the wrong reasons. Leading 1-0 from the first leg, as River’s players entered for the second half, they were attacked from the Bombonera stands by a fan wielding home-made pepper spray, an act that caused the game to be abandoned and the Millonario declared winners.Unsurprisingly, this time round absolutely no stone will be left unturned to avoid further trouble, particularly a repeat of the bus attack that left Boca’s Pablo Perez needing medical attention after glass from the vehicle’s shattered window scratched his retina. The last Superclasico on September 1 saw over 1000 police officers stationed in and around the Monumental, while the Boca coach’s entrance was done with the street totally sealed off to home supporters.The hope is that all eyes will remain on events on the pitch in two matches that bring together arguably South America’s strongest teams. With international stars like goalkeepers Franco Armani and Esteban Andrada on show, wily veterans such as Tevez, Lucas Pratto and, of course, ex-Roma idol Daniele de Rossi and the usual smattering of exciting young talents – River’s Exequiel Palacios and Lucas Martinez Quarta, and Boca pair Alexis McCallister, on loan from Brighton, and Emanuel Reynoso demand special attention – the stage is set for a fascinating cup tie that will show off the best of the continent’s football.It is clear though, as Ariel Ortega, the mercurial ex-River and Argentina playmaker and veteran of scores of Superclasicos, points out, that this will not just be another game. “If Boca come up 10 times, give them to me 10 times, even more after all that’s happened,” the retired star fired to La Pagina Millonaria .“If River go through again you’ll kill Boca’s fans, they’ll die. I speak to kids who are huge fanatics and they don’t want to play, you’ll bury them. These are beautiful games to play, no other game in the world can match this.”A win for the Millonarios over two legs would certainly be a mortal blow to their rivals, still reeling from 2018’s immensely painful reverse having led three times over 180 minutes. Victory for Boca, on the other hand, could well spell the end for River coach Marcelo Gallardo who, after delivering two Libertadores wins and establishing himself as one of Argentina’s finest trainers, may decide it is time to move on.Off the pitch, too, all eyes will be peeled on fans’ behaviour and possible violence hotspots, not least due to the sensitive period Argentine society is facing as a whole in the midst of economic crisis and fiercely-fought presidential elections.Whatever happens, then, the Superclasico will be headline news across South America throughout October and beyond, overshadowing even a game of the calibre of Flamengo’s meeting with Gremio in the ‘other’ semi. Just like 2018’s chaotic double-header, the latest edition of this most fierce of rivalries will make compelling viewing from start to finish.