There was one loud explosion and then six more followed. Across the city they knew that could mean only one thing: Real Sociedad had won again. A tradition from la Real’s old Atotxa ground, momentarily lost after they left in 1993 but recovered at Anoeta in 2009, a single firework is set off every time the visitors score and two are lit when la Real do. That way, the theory goes, in the boats on the Bay of Biscay they always knew how their team were getting on. And although moving to a ground on the other end of town means news no longer travels so far out to sea, and while one of these days VAR is going to ruin everything, Juan Iturralde still greets every goal by dashing through the gates and down the stairs rockets in hand, ready to tell the world.

This Sunday, he made the run from stadium to forecourt four times in less than an hour, heading out into the rain. A single rocket alerted to Betis’s opening goal, scored by Loren Moron after 12 minutes before two announced the equaliser 10 minutes later, an own goal from Javi García – a moment’s doubt introduced, as always, by the brief gap between bangs. Then came four more, two marking Willian José’s thumping finish to put la Real into the lead on 38 and two more following Cristián Portu’s neat finish to a lovely move on 58. Outside, they might not have been able to see the game, but they knew: after losing at Sevilla and against Getafe, a 3-1 win had taken la Real into a Champions League place ahead of Atlético Madrid and Sevilla on goal difference, just two points behind Madrid and three below Barcelona.

Only it’s not really enough just to know. It never is. As the former Real Sociedad manager Juanma Lillo, born and raised in Guipúzcoa, insists: “What enriches you is the game, not the result: the result is a piece of data. The birth rate goes up. Is that enriching? No. But the process that leads to that? Now, that’s enriching. Do you go unto a football stadium, in the last minute, look at the scoreboard and leave?” He’s right of course, and this time especially: it’s not enough just to know where la Real are, to ask if they can stay there, although they’re certainly good enough, or to note that seven of the men who played on Sunday came through the youth system and the entire starting XI cost less than Madrid spent buying Álvaro Odriozola off them; the really good part is seeing them get there.

Because here’s the thing: Real Sociedad are the best team in Spain right now. The best to watch, anyway. Maybe even the best-best. Sunday showed that.

So, in fact, might their previous two games, despite losing: defeat in Sevilla was the most enjoyable match of the season so far, and even after going down to 10 men and letting in a last-minute winner against Getafe fans went home “moderately happy”, coach Imanol Alguacil said: there were, he insisted, “good vibrations”. The forward Portu said: “It’s hard to have no doubts when you lose, but we were the opposite: we didn’t have the slightest doubt,” and nor did supporters. They would be straight back for the next game a fortnight later, even on a day so miserable that the hilltop church at the Fundación Zorroaga that looks down on the ground couldn’t see it through the rain.

This Sunday 28,032 went, which was Real Sociedad’s lowest attendance this season but is still ahead of anything from last year or the year before, and not just because the stadium is bigger now but because something is building at Anoeta. Redeveloped, running track gone, the Aitor Zabaleta singing section at one end providing a focal point for an atmosphere which is proving contagious, the place is officially now called the Reala Arena; more importantly, it is theirs, home at last. An enjoyable place to be with an enjoyable team.

In the build-up to Sunday’s game the Betis manager, Rubí, said that la Real were the team he liked the most, playing “lovely” football. One former Spain manager says they’re the best in the country right now. This Sunday they went one down against Betis but then took Rubí’s team apart with the kind of display that underlines why: fast, precise, technically impeccable at times, and relentless, the rain giving it an epic feel.

“They don’t run, they fly,” cheered El Diario Vasco. “A storm,” Radio Euskadi said; “a tsunami,” El Mundo Deportivo called them, taking advantage of the fact that before kick-off the Ramones had rung round on the PA system while at half-time it was Gatibu to declare the team “pure rock and roll, [with] electricity in their veins”. You could see why.

“Everyone goes at full pelt,” Portu said. But it’s more than pace; it’s precision too, the clarity of roles, the commitment to attack. “We all have a specific function and we all have to do something special to hurt the opponents,” Portu said. “And we have a lot of freedom to express ourselves.”

This was an expression of who they are. To take just two players, the men in the middle: Mikel Merino produced a performance that was startlingly complete while just ahead of him – well, everywhere really – Martin Odegaard has probably been La Liga’s best midfielder. He loves a scooped pass, a little dink, and from one of the three he played, Oyarzabal cleverly laid it off to Portu for an impeccable third goal that was Portu’s first here.

Real Sociedad are playing a thrilling brand of football under Imanol Alguacil. Photograph: Javier Etxezarreta/EPA

“It doesn’t get any better,” Portu said. But while this might have been la Real’s best performance, it wasn’t an isolated one. Sure, they lost against Athletic, but this is the team who took Atlético apart, took on Sevilla, the two trading blows, and were unlucky to lose against Getafe. A team who know exactly what they’re doing.

“After Getafe people said that maybe if we had been more conservative we might have got the points but no, not here: you have to go for them. And we win a lot of games because of that ambition to get goals,” Portu said.

Alguacil said: “The idea is clear: we will not wait, we won’t hedge our bets, we will always go for them, try to score as many goals as we can – and as long as I am sitting here, that will be the case.” And as long as he is sitting there, fans will sit in the stands.

“Fun,” El País called them this morning. It’s a simple word, but it might be the most important, the one that best defines them. Maybe it’s because this is a young team – Merino and Le Normand were born in 1996; Zubeldía, Guevara and Oyarzabal in 97; Odegaard in 98 – but there’s something about the way they play that’s contagious. There’s dynamism, determination. “You should see us training; if you did, you’d understand a lot,” Portu said. “Everyone’s full on. No one relaxes ever, not even on a Monday, when it’s our day off.”

That’s not just duty. There has to be enjoyment and that relentlessness speaks of an enthusiasm, an urgency that’s clear in Real Sociedad’s play. Every time they’re knocked down, they’re up again taking the free-kick immediately; every throw-in is taken fast, rushing to get every ball; even the ball-boys move quick. It’s part of a plan of course, but it feels like at some level it’s simpler than that: as if they just want a game, like they can’t bare the idea of wasting a moment. If there’s one thing more fun than watching la Real, it’s playing for them – and that’s precisely what makes them so good to watch.

“Being on the pitch is a joy,” Portu said. Being at the ground is a joy too, down where goals go in and fireworks go off.

Talking points

• There was no Bale, no Modric, no Kroos, and no Hazard, €268m worth of players missing, but the team Madrid put out there still cost €463.4m. The team playing against them cost €3m. Madrid’s players had 150 winner’s medals from major trophies between them; Mallorca’s total amounted to one Turkish league and one Polish league. Only four of the 13 players who made an appearance had played in the first division before. Six of them were playing in Spain’s regionalised, 80-team, anything-from-third-to-seventh-tier Second Division B 16 months ago. On the same day that Madrid were winning a third European Cup in a row. Their coach was there with them, just as Madrid’s was there with his team. You can see where this is going can’t you? At the start of the weekend, Real Madrid were top and Mallorca were in the relegation zone. By Saturday night, they weren’t. Mallorca, the first division’s newcomers, and a team still based on the team that were in the Second Division B two years ago and the Second Division last year, with the same manager and the same players, only went and beat Real Madrid 1-0. Lago Junior got the goal.

• Maybe it can work, after all? Maybe Barcelona do have a tridente after all? Griezmann, Messi and Suarez all scored in a 3-0 win at Eibar. Better still, they were all involved in the second and third goals together.

• Hallelujah! And yes, the radio here really did play that when Luuk de Jong finally got his first Sevilla goal – in the 88th minute against Levante.