Elche had waited long enough; they weren't going to wait much longer. It took a quarter of a century for them to return to the Primera División. Not since the fall of the Berlin Wall had Elche, founded in 1923 and one of the country's historic clubs, been here. Eight thousand, eight hundred and thirty-three days later, the Martínez Valero hosted a top-flight game at last, with 23,859 fans in attendance. One minute and 18 seconds later it erupted: Elche were in front. Five touches were all it took. Real Sociedad hadn't even left their half.

Actually, that's not quite true. After all, the rules do state that you have to pass the ball forward from the kick-off. So, la Real did. And then back it went: one pass, two, three, four … 10 … and then a loose one, given away. A touch to control it and Ferran "Coro" Corominas shot. Claudio Bravo saved but clumsily pushed it wide. In came the corner, skidding past everyone, and in went Coro again: a touch to control, virtually on the goal-line, and an easy finish.

For many fans, the great forgotten men and women of Spanish football, seemingly despised by those who run the show, this was a special week – a kind of opening day part two.

Betis were back and as noisy as ever, even as their match straddled Sunday night and Monday morning, even as they somehow didn't win. Málaga's fire sale continued in the summer, but so did ticket sales: the Rosaleda was a sell-out for the visit of Barcelona. And Athletic Bilbao played Osasuna … at Real Sociedad, a Basque* derby involving all three clubs. Athletic's new San Mamés stadium will be ready within the month but their first "home" game was played away, 385 official buses making the trip, 20,000 fans turning Anoeta red and white.

As for Getafe, they were celebrating a decade in Primera, a fact that drove home just how badly they have failed to get fans on board, despite having some pretty good teams and some pretty good managers over the past 10 years. On Friday night there were barely 4,000 in the Coliseum for the first home game of the season.

For the recently-promoted, it was particularly special. Almería, Villarreal and Elche all made their returns on a Monday night, which is not exactly the way they would have wanted it. Two of them faced each other, Villarreal winning 3-2 at Almería. And Elche were hammered 3-0 at Rayo, the side who this weekend lost 5-0 at Atlético; around 500 fans had travelled and made a lot of noise too, but it wasn't the same. This weekend, was another chance: a proper start. Villarreal returned to the Primera División and packed El Madrigal for a 2-1 victory over Valladolid that included two astonishingly good goals. And in Elche, the town surrounded by a palm forest, the excitement built.

A banner depicted Dr Emmett Brown's car: Back to The First Division, it declared. The club's anthem was sung a capella. The final touches had been made to the stadium, 22 VIP boxes and a paint job for Primera. In the 12th minute there was a standing ovation, in celebration at getting back up. And one local paper ran an homage to the players' wives, taking photos from the local fiestas: "lovely, elegant and nice, the ladies who will accompany our first team in the top division." Meanwhile, the coach, Fran Escribá, had warned them: at Vallecas they had been dangerously soft.

This time they would not be. For an hour, Elche flew into Real Sociedad, quick to the ball, surrounding their opponents, pressuring them. For an hour they were, la Real's captain, Xabi Prieto, admitted, "the better side … they had the chances to have won it". They racked up a dozen shots and Coro was everywhere. But, slowly, they ran out of steam and then Carlos Vela equalised. "We played very well indeed for an hour and against a great team. Everyone left their skin out on the pitch," Escribá said. "But the second half felt like a very long time."

The season may feel that way too, but at the start of last season no one expected Elche to get promoted; they have learnt to believe. The previous season they had fallen away at Christmas, dropping to 11th, and the season before that they had been beaten in the play-offs after finishing fourth, but they had spent 13 seasons in the Segunda División and never really looked like coming up. Escribá was in his first season as a head coach, having previously been Quique Sánchez Flores's assistant at Atlético, Benfica and Valencia and the squad was limited, by no means the best in the division.

But Elche won their first five games, for the first time in half a century; they went into top spot and never left it – leaders from first game to last. Unbeaten in their first 20 games, they set a new points record at the halfway stage of the season. There's something tough, steady about Escribá: a steel to his stare. Success was built on the defence; they were not always the most attractive team to watch. Twenty clean sheets and 22 victories, 15 of them by a single goal. Eight times they won 1-0; nine times they drew 0-0. Coro was their top scorer – on just 12 – and by the end of the season they had scored 54. Nine teams got more; no one had a better defensive record.

Yet of the four men who started at the back on Saturday, only Edu Albacar – the left-back with a wonderful touch who scored eight last season, five penalties and three free-kicks – is not a new signing. Alberto Botía came from Sevilla, David Lombán from Barcelona B and Ionat Sapunaru from Zaragoza. Nine players have come, including "The Rock" Carlos Sánchez in the middle of midfield and Manu del Moral up front. Loans and free transfers, all. It will take time for them to settle, while defensive solidity will be harder to come by than it was. Goals, too. The intensity with which they began on Saturday is going to be virtually impossible to maintain. It is early but it is hard to avoid the feeling that a step backwards is inevitable.

The talk has been of enjoying every minute but enjoyment may not be the key. This will be a struggle. A point against Real Sociedad was a start, and a good one against an excellent side, but it is only a point. This season will be hard, but then last season was supposed to be too. And Elche won't just await their fate. They have waited too long already.

Talking points

* Yes, yes, strictly speaking Osasuna are not really Basque. But try telling some of their fans that.

• Adriano did what Adriano tends to do: scored a belter from outside the area and then got injured. Barcelona beat Málaga 1-0 without Leo Messi but were hanging on by the end, with Víctor Valdés making a couple of vital saves. Neymar came on in the second half and was impressive: "In his head he is ready to start," Tata Martino said. Physically, the Barcelona coach clearly still fears that it is a different matter.

But it was what Martino said about the summer's other summer signing that most occupied the media, when he called the potential €100m fee for Gareth Bale "a lack of respect for the world we live in". "Tata has not been here long and he does not know how European football works, or his own club," Carlo Ancelotti responded. "Barcelona have spent a lot of money."

• Atlético Madrid were superb in their 5-0 win against Rayo. Rayo, on the other hand, were not. "We're the smallest, shittiest team in the league and unless we get that into our heads, we will not compete," the coach, Paco Jémez, said.

• And Valencia's coach, Miroslav Djukic, was heading in a similar direction, quickly discovering one of the ills that has so often afflicted the club. "I can't see any stars here," he said.

• Diego Castro: 15 penalties, 15 goals. Getafe twice came from behind to draw 2-2 with an Almería side for whom the outstanding performers were goalscorer Rodri, now joint top with Costa in the Pichichi charts, and on-loan Liverpool winger Suso.

Results: Getafe 2-2 Almería, Athletic 2-0 Osasuna, Elche 1-1 Real Sociedad, Espanyol 3-1 Valencia, Villarreal 2-1 Valladolid, Atlético 5-0 Rayo, Málaga 0-1 Barcelona, Levante 0-0 Sevilla, Betis 1-2 Celta. Monday night: Granada-Real Madrid.

Latest La Liga table