And then at last it happened: someone scored against Barcelona. There had been 31 goals since Villarreal striker Nilmar's clever strike when the league's third sexiest player out-sprinted Carles Puyol on Saturday night – and all 31 had been scored by the same team. Almería defender Santi Acasiete was the only non-Barça player to be have found the net in seven and a half matches when the man Don Balón's panel of 'experts' (or 'women', as they're also known) judged only marginally less attractive than Aitor Ocio and Fernando Llorente hit a clean, low shot past Víctor Valdés - and Acasiete had found the wrong one. The aggregate score in Barcelona v Their Combined Opponents was 31-0 when, in the 62nd minute of the eighth match, Daniel Pablo Osvaldo did what Almería, Panathinaikos, Real Madrid, Osasuna, Rubin Kazan and Real Sociedad couldn't do.

It could hardly have been anyone else for anyone else. As the ball hit the net, the roar made your ears bleed. Cornellà exploded. And so did El Prat (but more of him later). Perhaps Osvaldo had been right; perhaps Guardiola had. Perhaps they all had. This was, Guardiola announced, the hardest match remaining this season. It was the Catalan derby, Barcelona against Espanyol: the side that had produced the "Fuck of The Century" - which, given that it took 18 seconds, is a worry - to deny Barcelona the 2006-07 league title and had nearly done the same last year with a breathless, and goalless, draw that reopened the race; the side that Barcelona had only beaten twice in eight matches – their worst record against any team – and only thanks to a ridiculously ropey penalty in one derby and mighty questionable, mighty late one in another.

Moreover, Saturday's showdown was at Espanyol's new Cornellà-El Prat home where, under the watchful eye of their aggressive, clever coach Mauricio Pochettino and the Virgin of Montserrat, they'd won seven out of seven. And despite talk of truce, a battle was about to commence. Barcelona's new president Sandro Rosell had lunch with Espanyol's Dani Sánchez Llibre, which is more than can be said for Joan Laporta, while, Andrés Iniesta had become Espanyol fans' favourite player after celebrating his World Cup winner by revealing the message, "[Espanyol's late captain Dani] Jarque, always with us" and handing the shirt to his city rivals - his name was cheered when the teams were read out and when he was substituted, the entire stadium applauded, chanting. "Iniesta! Iniesta! Iniesta!" But those were temporary respites, Germans and English playing football in no man's land.

The banners were out – "Catalunya, more than one club"; "Barça by decree, Espanyol for feeling", "Welcome to Blue and White Hell", "This town aint big enough for the both of us" – and so was the deafening noise, the war cries. (So, sadly, were the monkey chants from some fans who oo-oohed Dani Alves all game, including when he confronted Carlos Kameni.) In midweek, Espanyol had released a video set to bellicose classical music which declared: "You're not opponents, you're the enemy." And Osvaldo, the team's top scorer, was promising to "paint Barcelona's faces". Now, amidst the din, amidst the intensity, pace and aggression, amidst the football and the 'other football', with Espanyol employing a high-line and enormous pressure, he had. It had taken 677 minutes but perhaps Barcelona were beatable after all.

Perhaps not. There was one flaw. Osvaldo had scored but the score was 31-1. More to the point, it was 3-1. Barcelona had scored three times already, through Xavi and Pedro. And while Espanyol rallied, while they had beaten Barça's defence – and the ease with which Osvaldo out-sprinted Puyol and the risk inherent in such a high back four may yet cause concern – it was soon 4-1. And then five.

Again.

This was the fifth time Barcelona have scored five. They have now got 51 after just 16 weeks. They have won 10 on the trot and racked up an eighth win out of eight away. They have dropped points just twice – against Mallorca and Hércules - to boast the best record in history at this stage. They finish 2010 with a record 103 points in the calendar year, the best league side in the world. With a Copa del Rey to come, Leo Messi has scored 58 goals in 53 games – the highest total ever. He has 17 in 13 league games and though he did not score on Saturday, his performance was once again strikingly complete and he now has 11 assists too.

All of which makes it sound like Espanyol were rubbish. But they weren't. All of which makes it sound like Barcelona did what they always do. But they didn't. Not quite.

Make no mistake, Barcelona were brilliant. But this was another kind of brilliant; the kind of brilliant that amidst the precision passing and movement often goes unnoticed – the kind that, as has been argued here before, destroys the clichés, the facile assumptions. Because on Saturday night, Espanyol did fight. More than anyone this season except Copenhagen (and, yes, that does include Hércules). Few, if any, sides have pushed so high against Barcelona, nor chased them down so quickly. Espanyol did battle, they did pressure, and they did take the game to Barcelona; they did, on occasions, succeed in taking the ball off them; they did rattle them, they did dive and whinge and protest. They did create chances.

Trouble is, so did Barcelona. Barça have conceded just nine goals this season. Not only had they gone seven and a half games without conceding any goals, they had barely conceded any chances. In the last six games, they had allowed just nine chances. In part, that is because of their ability to keep the ball: against Real Sociedad, Barcelona completed more passes than any team since Opta stats began, they occupy the top 36 slots for match passes since 2006, and the top four average passers in La Liga this season are all Barcelona players: they have nine in the top 14. Tiki-Taka is a defensive tactic as much as an offensive one, founded on the principle that if you keep possession the other team can't score.

But it is not just that Barcelona keep possession, it is that they win it. Conscious of their weakness without the ball, Guardiola has perhaps one obsession above all others: get it back. As one commentator put it this weekend: "Barcelona don't just play, they earn the right to play." At the start of the season, Valdés insisted that his side were getting even better. Not because of the skill but because, he said: "We have improved hugely in robbing the ball, in how little time it takes to get it back." That means intensity and aggression, chasing players down, pushing high – even if that is occasionally risky. It is no coincidence that those who commit the most fouls in the side are invariably the forwards. If Espanyol wanted a fight, Barcelona gave them one. If Espanyol's pressure was asphyxiating, Barcelona were the Boston Strangler.

As much as anything else, that was why they missed Eto'o and why Zlatan Ibrahimovic – although he was really pretty good and scored possibly the most important league goal of the season – did not fit. He offered a Plan B, sure. But he weakened the Plan A. Now, with David Villa, who has nine in seven league games, Barcelona have a bit of that back.

With Villa and increasingly with the man who, splashed across the cover of El Mundo Deportivo, embodied Barcelona's personality this weekend: Pedro Rodríguez. The man Barcelona's technical staff wanted to ditch before Guardiola intervened, who two and a half years ago was playing in the Third Division and is now a World Cup winner, who ended 2009 by scoring in all six competitions and, so often overlooked, has ended 2010 undisputed at last. Fast, genuinely two footed and a great finisher, dangerous racing through or coming in on a diagonal or horizontal run, Pedro has become a kind of better version of Ludovic Giuly. Barcelona have started five games with a Messi-Pedro-Villa forward line; in four, they produced manitas. Pedro has now scored six in seven games, including goals against Madrid and Espanyol, as Barcelona beat their two biggest rivals by an aggregate score of 10-1.

Those goals were key; the way they arrived was the secret. With speed, attitude and intensity; with edge, bravery and alertness. Beyond the precision passing, Barça's physical condition is impressive, the way they fight, the sheer speed with which they screech around the pitch, closing down space. The solidarity, the character, the competiveness. It was no empty rhetoric: Espanyol really should have been Barcelona's hardest game. And in some ways way it was. But still it finished with five goals. Barcelona always seem to have the ball. On Saturday night they showed they have balls too.

Talking points

• And so to El Prat: According to Marca's front cover on Sunday morning, Barcelona had been given a helping hand by the referee and in one of his truly surreal want-to-be-spiritual/political-leader videoblogs, editor Eduardo Inda moaned that someone is trying to hand the title to Barcelona before the year is out. Apparently, Marca said, there had been a foul on the first Barcelona goal and an offside on the second. Meanwhile, one television company proved that the third was offside with this sparkling piece of geometrical evidence. (Mind you, while their evidence is rubbish the offside might not be). Marca, whose refereeing expert Rafa Guerrero was famous for screwing it up (but who this column always defended) and has sold himself for a fistful of dollars was on hand to help prove that white is black. Yet again. Espanyol had complained that Callejón was down when Barcelona scored their first. To which this column can only respond: good. Well, actually, that's not the only response. There's also the fact that it was not a foul, Callejón was not hurt, no one stopped, and no one was caught out of position. Oh and that the fact that, having modelled his hair on Jedward, Callejón most certainly does not deserve the benefit of the doubt.

• José Mourinho had, in his hand, a piece of paper. He also had a few million arguments on his mind. He appeared in the press room after last night's match at the Santiago Bernabéu insisting that it had not been a match at all: "I don't want to talk about it," he said. "It was too ugly." He was right. It was a dreadful, utterly classless game, eventually won 1-0 by Madrid and only made entertaining – if you can call it that – by the cheating, fouling, whinging, gamesmanship and diving. Sevilla were rubbish, playing the kind of football that made you wonder if they thought they had John Fashanu playing up front. Mourinho did though want to talk about plenty of other things. It was one of those press conferences where journalists' mouths fell open as they shot each other glances, mouthing "bloody hell", barely able to believe that Mourinho was still going – and going deeper and deeper with every step. The hostias, as the Spanish say, were being handed out like breads. And barely anyone escaped as he stepped up the pace, a challenge in every word.

The piece of paper he was holding was a print-out on headed club paper showing "13 grave errors" from the referee. The paper, he said, had been handed to him by the club (and, however much, the spin doctors leapt into action, trying to downplay it, insisting the never-defined 'club' do the same every game, its very existence begs loads of questions). And anyway, Mourinho said he was furious at the fact that it was always his job to defend the team and talk about the ref: "We have a club, a structure, and I want someone to defend my team." He demanded a meeting with the president, blowing director general Jorge Valdano out the water by saying "if I can talk to the No1, why would I talk to anyone else?!"; revealed splits by saying: "Why can't we have a division of opinion?"; very, very pointedly remarked that his players need a break; and was quick to praise his team but absolutely nobody else. He even had a little bit of a dig at fans, on the night where most Spanish journalists thought they had really got behind the team in adversity (a ridiculous red card for Carvalho), saying: "I would like more." The underlying message seemed to be clear: Buy me my bloody striker! Now.

And then when he was finished there was even time for a quick laugh at Rafa Benítez.

• The last man to score against Victor Valdés before this weekend got another one on Saturday night – and it was a real beauty from Nilmar as Villarreal continue to play great football (except when this column goes to watch them). But even better was Tino Costa's rocket for Valencia. The kind of goal Johnny Metgod would be proud of. Boom!

• Real Oviedo failed to win on the pitch on Sunday. Yet again. But they could be about to win the most important battle of all. Fans from the club - who are playing their football in the Second Division B following relegation and financial crisis at the start of the decade – held a 3,000-strong demonstration on Sunday. Having saved their club once back in 2003, they have watched helplessly as the current board sink the club into even greater financial crisis and on-pitch failure. Now, at last, it looks like the board might be on their way and new owners may soon be taking over. One of the country's historic clubs, they have been away for too long.

Results: Espanyol 1–5 Barcelona, Málaga 0–3 Atlético, Osasuna 0–0 Zaragoza, Almería 2–3 Getafe, Real Sociedad 1–2 Valencia, Deportivo 1–1 Sporting, Villarreal 3–1 Mallorca, Levante 1–2 Athletic, Real Madrid 1–0 Sevilla,

Racing-Hércules, tonight.

• Latest La Liga standings