The opening weekend of the football season is one when hope, however temporary, triumphs over all else. In August 2007 this was the case for Sevilla, who were riding the crest of a wave. Three months previously they had retained the UEFA Cup in Glasgow, the first club in the competition’s history to do so. Indeed, in the space of 15 glorious months, Los Rojiblancos won five trophies, including their first Copa del Rey title in 59 years.

Genuine hopes emerged that the Andalusians could break the duopoly and omnipotence of Barcelona and Real Madrid – after all they had finished only five points off the Spanish league crown in 2007. But there was a rivalry much closer to home that was growing increasingly toxic.

The city of Seville itself is how most people envisage Spain from afar; the home of bullfighting and flamenco music is loud, colourful and hot, sometimes unbearably so. The river port is without doubt one of the most beautiful locations in the whole of Europe. It’s home to a magical Plaza de España and a magnificent Old Town but it also hosts what is traditionally the most competitive inner-city football rivalry in all of Spain.

Uptown, Sevilla, and downtown, Real Betis, both reflect the city’s characteristics and mirror them in football, often spectacularly. Sevilla’s Ramón Sánchez Pizjuán is located in the city’s swanky business district, with an encapsulating tiled stadium front of club badges from Spain and around the world. A notable absentee from that display are city rivals Betis, whose Benito Villamarín home is located in the south of the city. Unsurprisingly it has been a long-term grumble of Los Verdiblancos that the city’s metro line does not stretch to their side of the city, fitting the argument that Sevilla have been the establishment’s team and consistently shown favouritism.

The stadiums combined hold 100,000 spectators – over a seventh of the city’s population – yet more often than not the clubs’ passionate fans pack the grounds to the rafters. Talk to a local and the chances are that they devote their allegiances to one club or the other (a rarity itself in Spain where Real Madrid and Barcelona dominate – a recent survey showed that the two powerhouses are supported by 77 percent of the country’s football fans). The Andalusian capital is one where loyalties run deep, and often split families down the middle. Most would now describe the rivalry as ‘friendly’, but the reality as recently as 2007 was very different.

Sevilla kicked off their 2007/08 campaign by hosting Getafe, whom they had defeated three months earlier to lift that historic Copa del Rey. The Sánchez Pizjuán was typically deafening as the home fans were in party mood even if the match itself didn’t accurately reflect the vibrancy in the stands.

In the 35th minute, a Getafe attack petered out and the ball drifted out of play for a Sevilla goal kick. Goalkeeper Andrés Palop gathered the ball to restart the game quickly, but his attention was diverted by teammate Ivica Dragutinović – the Serbian defender had sprinted back towards the byline where Antonio Puerta had fallen to his knees and collapsed.

Both sets of players realised something was amiss and frantic signals were made for medical staff to rush on and attend to Puerta, who appeared to be writhing on the ground in agony. An eerie hush fell over the stadium as a sense of bewilderment mixed with anxiety took hold. The feeling was temporarily replaced by relief as the wing-back got back on his feet and was helped off by the physios and substituted.

What unfolded was not played out in the public eye, but will never be forgotten by anyone in Seville that day. Puerta had been accompanied back to the dressing room by doctors; despite receiving medical attention, he collapsed again. He was resuscitated by the medics and rushed by ambulance to the intensive care unit of the local Virgen del Rocío hospital – all captured in dramatic televised footage.

Three days later, the Spain international passed away. Details began to emerge of the tragedy; the 22-year-old possessed an incurable, hereditary heart disease which brought on prolonged heart attacks, resulting in multiple organ failure and irreversible brain damage. It stunned the club, the league, the nation, and the wider footballing world.

The heartbreak was only sharpened as Puerta’s girlfriend, Mar Roldan, was heavily pregnant with his son. Aitor Antonio Puerta Roldan was born two months later, fatherless, but he was immediately made a lifetime member of the club.

Puerta was more than just a highly promising player, he was a Sevillista since birth thanks to his father who played for Triana Balompié, and he grew up a stone’s throw from the stadium; the street he grew up on was later renamed in his honour. He was highly talented, too and had been scouted extensively by both Arsenal and Manchester United.

One moment of Puerta’s brilliance defined the club’s progression, striking a spectacular left-footed volley in the 100th minute – in the club’s 100th year – against Schalke in the UEFA Cup semi-finals. Sevilla won the game 1-0, and demolished Middlesbrough 4-0 in the final, sparking the club’s remarkable 15 months of unprecedented success.

The event rocked the city to its core, not just those in Nervión but also in the Betis stronghold of Heliopolis, which contemporarily was quite startling, the mutual enmity between the clubs had seemingly peaked and the existing relationship was ice-cold. In Spanish football this is known as morbo – a word which has no direct translation into English, but essentially it covers the factors that fuel and act as a catalyst for an intense rivalry.

Differences in identity, both culturally and politically, are as intense and relevant in Spain as anywhere in the world, and that is why morbo is so important. Indeed, Morbo was the title of the superb, encapsulating book written by English journalist Phil Ball in covering the story of Spanish football for an English-speaking audience.

Ball describes the morbo between the Seville sides in ‘Grand Canyon proportions’, outlining the social difference between the clubs in as stark terms as the “bourgeoisie” Sevilla and “proletariat” Betis, and how this is unparalleled in any other Spanish region. Yes there are fascinating identity differences across Spain – in Catalonia between Barcelona and Espanyol, in Asturias between Sporting Gijón and Real Oviedo, in Madrid, even if suburban Rayo Vallecano are the capital’s true alternative to centralism and the real representative of the working classes – but none quite parallels the social difference in the Andalusian capital.

In 1949, for instance, Francisco Antúnez trod along the less-travelled path between managing Real Betis to taking the reins at Sevilla. The global communist authority of Radio Moscow said of the move: “Sevilla, the capitalist team of the city, have trampled upon their proletarian neighbours Betis, abusing the power handed to them by the fascist Francoist regime.”

These social differences may have narrowed and mellowed over the decades since but, nevertheless, the vitriol between the pair reignited spectacularly in the 1990s. Local businessman Manuel Ruiz de Lopera took control of Real Betis in 1992 and he oversaw some glorious times for the club, including their 2005 Copa del Rey triumph and subsequent Champions League campaign, which included a 1-0 win over José Mourinho’s Chelsea.

Controversy, however, was never far away. The world-record signing of Denílson turned out to be sensationally underwhelming, while Lopera even renamed the Estadio Benito Villamarín after himself, a decision which has since been reversed. The fans were sick and tired of his constant flirtation with controversy and dodgy dealings.

Lopera was self-made and subsequently an egotist, and was central to the stoking up of tensions in the city. In 1999 Sevilla were in the Segunda, pressing hard for the playoffs and up against Albacete on the last day. The match ended 1-1, and the Betis owner was accused of giving incentives to Albacete to ensure they got a result. De Lopera’s response was startling: “I reserve the right to do as I wish.” The subsequent acceptance that this was standard practice once again demonstrated the moral bankruptcy within the Spanish game.

A year later, it was even worse. Sevilla did eventually achieve promotion in 1999 but their stay in the top flight didn’t last long; going into the last day of the following season they were rock bottom and relegated. They were hosting Real Oviedo on the last day, with the Asturians needing a win to stay up. Who would Oviedo ensure went down in their place? Betis, of course.

Sevilla trailed 3-0 at half-time in a pitiful performance, and had Norwegian goalkeeper Frode Olsen not pulled off a number of world-class saves, it would have been much worse. Olsen was substituted at half-time and he claimed later that Sevilla would happily throw the game to ensure Betis went down. And that season they did; no investigation into the events ever took place.

Matches subsequently became labelled ‘high risk’, with a heavy police presence evident throughout the city. Fans of Los Rojiblancos who made the 50-minute walk along the Guadalquivir river between the centre of the city and Heliopolis had to do so marshalled by a police patrol; the picturesque, tranquil scene transformed into one where you could cut the tension with a knife.

De Lopera was not the only controversial owner; Sevilla had one of their own too. José María del Nido was club president until late 2013 when he was jailed for corruption. In February 2007 perhaps the most bizarre in a series of unedifying incidents took place in the Betis presidential box, after del Nido refused to be seen in public with a bust of Lopera (del Nido had insisted he would turn up to the box come what may, despite Betis publicly stating he wouldn’t be welcome). An open fist fight ensued between board members. The following month, Sevilla boss Juande Ramos was knocked out cold when a glass bottle thrown from the Betis section struck him on the head.

Other dark images will live long in the memory from this period – rockets were launched from both sets of fans into the other, seats were ripped up and thrown onto the playing area and sets of ultras clashed outside the stadium. The two egotists in charge of the clubs seemingly thrived in this environment. “Betis and Sevilla is a flammable mix. And the worst thing is, it is one that’s in the hands of pyromaniacs,” wrote AS editor Alfredo Relaño.

All those frightening events unfolded when Puerta was blossoming into a superb player in the midst of Sevilla’s success both nationally and on the European stage. It took such a harrowing, blood-chilling incident for the two presidents’ childish antics to be banished from the forefront of people’s minds, but no-one could quite believe just how far the differences between the two would be set aside.

Tens of thousands lined the streets of the city surrounding Sevilla’s stadium as Puerta’s coffin was carried through before eventually arriving at the Ramón Sánchez Pizjuán stadium. Spontaneous applause and chants of “Puerta amigo, Sevilla esta contigo” (Puerta friend, Sevilla is with you) were chanted. Many simply broke down in tears.

Members of the Sevilla and Betis squads, many of whom were in tears, returned in the morning to pay a final tribute to the player together with delegations from clubs all over Spain and Europe. Sevilla’s players had just returned from Athens where their Champions League clash with AEK had been postponed due to the tragedy.

Shortly before midnight, the official delegation from Real Betis showed up, headed by de Lopera. The Betis president was red-eyed and had visibly aged since his last public appearance. The image of him shaking Del Nido’s hand before both broke down and embraced each other is one that will never leave anyone that was present that night. Mourning and sorrow had brought unity and humanity.

De Lopera spoke to Canal Sur later that night: “Betis and Sevilla are brothers … Antonio Puerta has sent us a message of unity from heaven.” The Sevillistas present openly applauded, but the long-term impact proved much more profound. The ins and outs of the incident have been debated at length – was this a calculated move by De Lopera? Was it out of self-interest? Did Del Nido want to be seen in the arms of his greatest rival?

None of that matters, the rivalry since has been shaped by that night, with the two neighbours co-existing in an atmosphere totally unrecognisable from that which preceded it. The symbolism of those images proved powerful and enduring, and they did more than just plaster over an open wound – they acted as a magic lotion.

Five years later tragedy once again struck the city as Real Betis defender Miki Roqué passed away from cancer. He was 23-years-old. The former Liverpool youth player was diagnosed with pelvic cancer in March 2011 when he had undergone a routine medical check for back problems. The club, the city and the country sought ways to raise vital funds for his treatment, as Roque immediately announced his retirement from football.

Roqué’s mother was born in the town of La Pobla de Segur, which lies just three hours northwest of Barcelona; it is there that the defender withdrew from the public eye and underwent his treatment. This town was also the birthplace of then-Barcelona skipper Carles Puyol, who began to forge a close relationship with his fellow Catalan.

In the aftermath of Barcelona’s 2011 Champions League win over Manchester United, Puyol used the celebrations to don an ‘Anims Miki’ t-shirt. Puyol – who throughout Roqué’s illness underwent surgery for serious and prolonged knee injuries – witnessed his friend’s treatment first hand and their friendship became so close that the Barcelona defender made the remarkable, and understated, gesture of paying for all of his medical expenses.

Despite all the support across Spain, Roqué died in June the following year, two weeks before his 24th birthday. He missed Spain’s 2012 European Championship triumph – but Cesc Fàbregas, Pepe Reina, Álvaro Negredo and Gerard Piqué all paid tribute to him in the victory parade.

Betis manager Pepe Mel combined football management with his hobby of writing novels, but there wasn’t an ounce of fiction in the former West Brom manager’s letters to Roqué in the tough final weeks: “Do you remember when you called me to cheer me up when the team was going through that bad run?” he said. “You, who were fighting a life-or-death battle, were cheering me up. Thank you for making me a better person.”

Those words have a sentiment so strong and lasting that they embody the growing sense of maturity in the rivalry between the two Seville clubs, “los hermanos” in de Lopera’s words.

Sevilla have rekindled the glory days of the mid-2000s, with back-to-back Europa League wins and a club structure and business model which is envied across Europe. Real Betis, at time of writing, have just regained top-flight status as they romped to the Segunda title under the re-hired Mel. Los Verdiblancos had a higher average attendance than three-quarters of LaLiga clubs, including Sevilla, and the Primera will be delighted to have them and this fascinating rivalry back where it belongs.

By Colin Millar @Millar_Colin