Ramón Rodríguez, ‘Monchi’, walked out the door and refused to look back. Sevilla’s sporting director left the Sánchez Pizjuán after their 2-1 victory over Leicester City on Wednesday night with “mixed emotions”, insisting as he went: “All I’m thinking about now is the derby.” Now? That was all most of them were thinking about already, even before the game – or so it felt. Witness the scene that same afternoon. In the hotel where the squad meets before matches, there were a little under four hours to kick-off on a potentially historic night: the chance to reach a European Cup quarter-final for the first time in 59 years, the second in history. But, whispered one member of the coaching staff, sighing slightly: “Everyone in the city is talking about Betis.”

Joaquín Sánchez once insisted: “There’s no derby like this, not in Spain: Barça-Madrid is a joke in comparison.” And for years it seemed Real Betis Balompié and Sevilla Fútbol Club enjoyed winding each other up. Things are a little calmer now, and a rivalry that was all the stronger because there wasn’t one obviously bigger, better team, has become a bit one-sided over the last decade, but there’s still something about Seville, city of passion and humour, and something about Sevilla-Betis too: the biggest derby in Spain, “a game without compare in Europe”, claimed one local paper, and always there – even when it should be eclipsed, or rendered irrelevant. “Forget Betis,” that coach said. Trailing by 25 points, it wasn’t as if they were going to catch up. But how can they forget Betis? And how can Betis forget them?

So it was that three days later, on Saturday afternoon, fans gathered outside the same hotel, flares in hand, giving the team bus a guard of honour as it set off to cross the city. A banner read: “Don’t let these people down.” The day before, the Betis manager Víctor Sánchez del Amo had described the derby as the “exaltation of feeling in football”, and insisted his side had “a historic opportunity”, although it was Sevilla for whom the derby really offered a historic opportunity – if, Jorge Sampaoli said, they could just forget that it was a derby. The thing is, even as the Sevilla coach sought to talk objectives not opponents, he delivered a line that was more ‘derbified’, more pointed, than he probably intended. “You can take this game as one whose only aim is to make fans happy,” he said, “or treat it like us and think about reaching the top.”

If that contradicted his own love of what he calls “amateurism”, seeking glory in every game, there was logic in it: for a game like this, Sevilla’s staff knew, it was better to calm players down than crank them up. Besides, Sampaoli was right: the match mattered but, beyond it, the target was there. Sevilla walked out 66 hours after they had walked off against Leicester and did so knowing that victory would see them lead the league; Betis did so trying to stop them.

Huge cut-out letters hauled on to the pitch spelled “The Big Derby”, a green and white mosaic covered the stand with the slogan “an entire life dedicated to you”, and there was mass karaoke at the Benito Villamarín, words to Betis’s anthem displayed on the giant screen, letters going green – “Betis, so Betis, the thing I most love in the world” – as fans belted it out. All 41,263 of them. Work on one end meant that for only the third time there were no away fans. But, Sevilla’s captain Vicente Iborra later said: “We were turned on by the idea of being 11 against 45,000.”

Monchi, meawhile, had insisted: “Those who think we’re alone are wrong: there will be thousands of hearts beating in those 11 badges.” Below the message, a photo of a banner from the Pizjuán before a previous derby: “More than my heart, what beats is your badge.” A former Sevilla goalkeeper and sporting director for more than 15 years, but probably now in his last season at the club, Monchi’s view was different from his coaches’: “I want our players to feel what it’s like to win there,” he had said the night before.

Come matchday, it didn’t look likely. “Now, Betis, now, don’t stop attacking,” runs the anthem – and for the first half they didn’t. “Now, Betis, now, because the goal will come,” it continues – and it did. The surprise was that it was only one, Riza Durmisi’s free-kick flying through a gap in the wall, the first goal they had scored in a derby since 2013. Betis were going all Sevilla on Sevilla: intense, fast, pressing all over the pitch. The noise was deafening, a roar greeting every tackle, whistles accompanying every stoppage, screaming injustice. No patience, no waiting: just go. And they did; Sevilla were overrun. The first foul arrived on 27 seconds and the shots were not far behind, all of them at the building site end. Once they started, they didn’t stop. Rubén Castro had four in the first quarter of an hour. Thirty minutes later, the count read: 12-1.

Sevilla had not faced as many shots in the first half all season. In the stands, one director admitted that he wanted to find a hole to climb into; this was horrible, and so unlike them. In the dressing room, Sampaoli told his players that they had been let off; they were fortunate to be in the game at all. The good news was that they had been here before: five times they had come back to win games they were losing. It was about to be six. Substitutes had also scored more goals for them than for anyone else: 16 of 50. And that was about to be 17 of 52. “Judging by the first half, it was impossible to come back,” Sampaoli admitted later. But changes came, starting with Iborra, sent on alongside the previously solitary Steven N’Zonzi, and the balance tilted.

“We drew on our pride,” Iborra said. They also drew on their height, Víctor insisted. Sevilla gained a little control; Betis’s momentum had gone, impossible to maintain the tempo of the first half, even against a team that had rested little; and two free-kicks curled in from the right led to two headers and two goals scored from close range, the first from Gabriel Mercado – who has now scored three goals for Sevilla, two of them against Betis – and the second from Iborra. The latter arrived with a strong hint of offside. “Pure derby,” ran the cover of Estadio Deportivo the next morning. “A half each. Three goals from set plays. Refereeing controversy. More emotion than football. And a sixth comeback for Sampaoli securing Sevilla’s hegemony.”

As the ball hit the net, Iborra grabbed at the badge on his shirt and raced to the corner. “This is the best badge there is and scoring today made it all the more so,” he said, sounding like an addict: “This club is special: once you try it, it’s impossible to kick it.” On the touchline, Sampaoli screamed and clenched his fists, face as red as the shirt. The team’s shirt, that is, not his – the referee had made him take his red top off as he was mistaking him for a player. Which, given the miles he was racking up on the touchline, was probably fair enough.

At the final whistle, Sampaoli leapt into the arms of his assistant Juanma Lillo and then hurried down the tunnel. Sevilla’s players gathered together in a circle in the middle as Betis’s trudged off, one by one alone, the image of triumph and disaster. Sevilla ended the game with more than twice as many points as their rivals. For all the passion, for all the moment, that was the wider picture, the reality. It is the reality.

Jorge Sampaoli and the Sevilla bench at full-time. Photograph: Cristina Quicler/AFP/Getty Images

For the first time since Víctor took over, Betis had been beaten at home – and it had to be them. “It’s hard to explain,” Germán Pezzella sighed. “The fans didn’t get their reward,” Víctor said and while this was different, it was depressingly familiar too. The derby stats this century read: Sevilla 17, Betis five, draws 12. Betis have not won a derby at home for 11 years and Sevilla have won nine trophies since then. Betis have suffered two relegations in the meantime. Now, there is a tiny risk of a third, seven points separating them from the drop zone. “It’s hard,” Dani Ceballos admitted, describing the goals given away as “childish”. “If we carry on like this we’ll be in the shit until the final day,” he said.

As for Sevilla, they’re looking up. Or should that be ‘down’? On Saturday night, there was no one ahead of them, after all. “Blessed be the day that you invaded my life,” Monchi tweeted with a picture of himself sitting in the stands at the Sánchez Pizjuán right where it says You Are Sevilla. “This wasn’t any derby … how I love you, my God. You’re my life.” Under the stand at the Benito Villamarín, along the corridor where the dressing rooms are and past a mini trophy room, he was beaming, embracing friends. They all were. A metal shutter was raised and they walked out to the bus, surrounded by police vans outside. It was quiet out there now, unlike when they had arrived. The noise awaited them four kilometres away.

As they boarded, they were top of the table. They knew it wasn’t likely that they would stay there – Barcelona went to Atlético the next day to momentarily take top spot from them, and then Real Madrid moved ahead of them both with a 3-2 win at Villarreal on Sunday night – but it was still a significant step. Sevilla have played well for much of the season, finding themselves quicker than anyone imagined, despite a revolution at the club. Favourites to reach the quarter-final of the European Cup for the first time since 1958, the second ever, the question now being asked is if they could win a first league title since 1946, and that too would be their second ever. Why not? On Saturday, mostly they didn’t play well, but they found a way to win and they have now got 52 points – their best ever total this far into a season and a total that only Madrid, Barcelona and Atlético have ever matched.

Sevilla have collected 25 of the last 30 points, losing just once in 10, and Madrid and Barcelona are within three points, and they dare to say what others usually won’t. “For now, the word is hope,” Iborra said. “Betis are one of the teams that did us the most damage but after what we did in the second half we can think and dream of continuing at the top of the table: we’re competing for the league,” Sampaoli insisted.

Yet that wasn’t the only reason why the fans waited for them when they arrived back at the hotel on Saturday evening, cheering and clapping, welcoming them home as heroes; it was because they had beaten Betis, who had always been on their minds.

Talking points

• And so they took it in turns. First Sevilla went top, then Barcelona, and then Real Madrid. None of them completely convinced, but all of them won. This is looking like being a tasty title race, after Madrid were defeated by Valencia in midweek. For much of Sunday night, it looked like they were going to be defeated by Villarreal too. Hugely impressive, the ball moved slickly all over the pitch, Fran Escribá’s team took a deserved 2-0 lead, but they couldn’t hold on to it. Perhaps in part because they tried to. “Isco change the game a bit,” Zinedine Zidane said, and his introduction made a huge difference, Madrid finally taking control for the last half an hour. So, it was tempting to say, did Villarreal’s changes. So too did the penalty given for a handball against Bruno, which gave Madrid the equaliser and sent everyone crazy. “I can’t cut my arms off,” Bruno said (although someone some day is going to suggest that here). And so, from 2-0 down, Madrid came back and won it 3-2, Bale heading in the first and Álvaro Morata heading in the winner either side of that Ronaldo penalty.

• As for Barcelona, a late Leo Messi goal gave them a 2-1 win at the Calderón, where as one Spanish journalist put it, they didn’t so much play on grass as play on Velcro – the surface left long and dry. It was a cunning ploy but, Luis Enrique claimed afterwards, one that might have come back to bite Atlético. He reckoned that the goals were aided by a slow pitch and that a promising break for Antoine Griezmann broke down because of it too. It wasn’t a great performance from Barcelona, but it was a great result. Marc-André ter Stegen was probably their best player while for much of the game, only Neymar was offering them a way out from the pressure they were under, their best outfield performer. “The result probably wasn’t deserved,” Simeone said. (You can read the match report here.)

Lionel Messi scores Barcelona’s winner. Photograph: Denis Doyle/Getty Images

• Poor Sergio Asenjo was taken off during Villarreal’s match against Madrid, with the fourth cruciate knee ligament tear of his career. Spain’s outstanding goalkeeper this season, he was on course to win the Zamora award but he can’t now. It has a 28-game minimum and we’re 24 games into the season. More important, of course, is him coming back at all. For a fourth time.

• Tony Adams is at Granada, restructuring the club. Yes, that Tony Adams. And there is work to be done. It was 11 nationalities against one (well, two … or maybe three, depending on how you look at it) at San Mamés, where Athletic beat Granada 3-1, leaving them second bottom. They’re reacting at home, but not yet away.

• The bottom three is the same as ever, but things do look a little different this week. On one afternoon, Leganés scored a fifth of their goals this season, battering Deportivo 4-0, to leave them in danger of dropping into the relegation zone, which lingers just two points below them now while Leganés climbed four points clear. It was Garitano v Garitano at Butarque and it finished with Asier winning and Gaizka sacked. The favourite to take over at Depor is Pepe Mel.

• “We’re so lucky Iago Aspas plays for us,” Celta’s manager, Toto Berizzo, said after he slipped a clever free-kick under the wall in Gijón. Sporting might have got more, but ended up hanging on.

• Eibar: what a very, very, very good team they are. As for Málaga, they’re not.

• Quique Setien: don’t ever change. People will tell him to, but is that really a guarantee of anything? Las Palmas lost their fourth game in a row – and they’re likely to lose their fifth on Wednesday at the Bernabéu – but they shouldn’t have and it would be short-sighted to throw out everything they’re doing now. They lost 1-0 to Real Sociedad after goalkeeper Javi Varas played the ball straight to Xabi Prieto, leaving him with an open goal on a night when the home side had loads of chances and should have won, but didn’t. They haven’t won now since Alen Hallilovic and Jesé turned up, not that it’s actually their fault. “Did Real Sociedad deserve to win?” Prieto was asked. “Certainly not,” he replied. Class.

• And for all the refereeing controversy, the penalties given to Espanyol and Sporting were far worse than the one given to Madrid. But it’s only Celta and Osasuna and who cares about them, right?

Results: Las Palmas 0-1 Real Sociedad, Eibar 3-0 Málaga, Leganés 4-0 Deportivo, Real Betis 1-2 Sevilla, Alavés 2-1 Valencia, Espanyol 3-0 Osasuna, Atlético Madrid 1-2 Barcelona, Villarreal 2-3 Real Madrid, Athletic Bilbao 3-1 Granada, Sporting Gijón 1-1 Celta Vigo.