With five minutes to go on the opening day of the season Real Madrid's hopes of winning the league were slipping away. Then their new hero rode to the rescue. Francisco Román Alarcón Suárez, 'Isco', signed from Málaga for €30m and wearing No23, leapt above everyone to meet Marcelo's cross, powering a header past the Betis goalkeeper Stephan Andersen.

It was the first header he had ever scored. The Bernabéu erupted, a huge relieved roar, and Isco ran towards the fans at the south end of the stadium before disappearing under a pile of bodies. Across the city, AS drew up its front cover. "Hope is called Isco", it ran. From a 1-1 draw to a 2-1 victory. The title race was back on.

Now, that's an enormous exaggeration, of course. But there is something in it and the absurdity of the opening line is pretty much the point. It was almost midnight when Isco rose above everyone for a second time, emerging from the dressing room and climbing atop the metal 'box' to face the cameras to declare: "It was fundamental to win."

He was probably right. For Spain's big two, draws have long been the new defeats. Over the last four years, from a possible 114 points, the team twho have won the league have racked up 100, 100, 96 and 99 points (compared to 89, 86, 80 and 86 in England) and, with Madrid and Barcelona strengthening and everyone from third to ninth losing their best player, those figures might be bettered. Two points is a lot of ground to cede, even now. Madrid's challenge ended in the first four weeks of last season. That creates a whole new type of pressure; for Barcelona and Madrid, a kind of knock-out mentality has reached the league. Winning is an obligation, right from the start. Matching your opponents is a must.

It took just two minutes and 35 seconds of the season for Barcelona to score. It took Leo Messi nine minutes more. After 23 minutes, Dani Alves – now wearing 22 in honour of Eric Abidal – made it three; on 26 it was four and on 42 it was five. By half-time against Levante, Barcelona were winning 6-0. And all that with Neymar watching from the bench.

Asked what he had changed, the coach Tata Martino insisted: "Why would I change anything? I love Barcelona's style. What we have done, if anything, is recover things that Barcelona did but had stopped doing." There will be sterner tests, starting with Atlético Madrid in the Super Copa on Wednesday night, but the most important of those shifts was the pressure, always Pep Guardiola's great obsession: Barça pushed higher, robbing the ball earlier, denying Levante any room, suffocating them. "The pressure is the key," Sergio Busquets said. "We'd stopped doing things we used to do," Alves added and Xavi admitted: "While Tito was away [ill] we didn't do the tactical work."

When Madrid kicked off, Barcelona had just finished. They had scored seven. Madrid were determined to be even quicker. It took them one minute and 59 seconds to get the ball in the Betis net. The 'goal', bundled in by a defender, was correctly ruled out for offside. Three more would be too. But if that suggests Madrid cruised to victory, the truth was very different.

Madrid were weak at the back, Sergio Ramos in particular, and open in the middle; Carlo Ancelotti complained afterwards of the lack of "balance" and the space between lines, with Luka Modric and Sami Khedira finding themselves distanced from then men ahead of them. Cristiano Ronaldo's position was an awkward mix of centre-forward and left winger. Mesut Ozil and Isco, two men at their best behind the striker, were in wide(ish) positions they're yet to make their own, later switching sides. And Karim Benzema was often offside. Dani Carvajal was confronted by Cedric Mabwati, the man with a €1.20 buyout clause and devastating pace.

Nor was Mabwati alone: this summer, Betis lost both central midfielders, José Cañas and Beñat, but Joan Verdú, signed from Espanyol and it was he who controlled much of the game. Betis had the first four shots: the third went in, the fourth should have done. Benzema equalised but still Betis came. Nosa smashed a header against the bar. By half-time, including posts, the shot on target count read: Betis 6-3 Madrid. "But when you come here," said the Betis manager Pepe Mel, "you need to score two." It looked like they might not: Ronaldo hit the bar 30 seconds into the second half and Madrid rattled off 13 shots to Betis's one as the visitors faded, only to create little as the game ticked into the final 15 minutes, a draw becoming increasingly likely. Until Marcelo crossed and Isco scored and the tension lifted. Hay Liga! as they say. There is a league.

There is, too. And not just at the top. The first goal of the season was scored by Real Sociedad's Carlos Vela and it was gorgeous. Almost as good was la Real's second, dinked in by Haris Seferovic, as they defeated Getafe 2-0. Athletic Bilbao's first in a 2-1 win against Valladolid was superb too and Beñat, who made it with Ander Herrera, was as exceptional as everyone expected. Patxi Puñal scored on the first day of his 17th season at Osasuna but Granada got two and, under Lucas Alcaraz, promise to be worth watching. Diego Costa, everyone's favourite wind-up merchant but also a brilliant striker too, scored one on Sunday and another on Sunday as Atlético beat Sevilla 3-1 in the 11pm kick off. Before the second Diego Perrotti scored a belter and just before 1 am, Cristián 'Onion' Rodríguez got a brilliant third. And then there was Betis.

If Valencia v Málaga was ultimately disappointing, a glimpse of two debilitated former Champions League teams, there's something sadly telling about the league forcing the three newly promoted teams to wait until Monday for their big night; and if there was something predictable about Madrid and Barcelona winning, when it came to the performance at the Bernabéu it was less predictable. No walkover, no easy victory. This was a proper game against a proper team. "This is a performance to be proud of," Mel said. "I asked the players if they had enjoyed it and they said yes."

Over in Barcelona, it was a different story. The best thing that Levante could say about their trip to Camp Nou was that it was over. "We've left the dentists'," coach Joaquín Caparrós said. "Now it's someone else's turn."

Results: Real Sociedad 2-0 Getafe, Valladolid 1-2 Athletic, Valencia 1-0 Málaga, Barcelona 7-0 Levante, Real Madrid 2-1 Real Betis, Osasuna 1-2 Granada, Sevilla 1-3 Atlético. Tonight: Rayo-Elche, Celta-Espanyol, Almería-Villarreal.

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