20.08 – So here we are: the big one. And, for a variety of reasons, this doesn’t just feel like a routine fixture. Without wishing to delve into Sky Sports style hype and bombast, there is genuinely a lot on the line in this Clasico. Win and, given how small the margin for error is in Spain, then Real will take a long stride to the title already. If Barcawin, however, it’s very much open season. Even more so, it could have an effect on the Champions League and any future meetings given how far ahead of the pack these two look.

20.32 – A few interesting dynamics to this match tonight. When both these teams are at their very best, it would be hard to argue that Barcelona are not the better side. As we’ve said many times in the past, no team in history has ever forced opposition teams to play on their terms to such an extent.

But the key question tonight is whether Barca are actually at their best. Real certainly are, having won all of their last 15 games with an aggregate score of 57-9. By contrast, Barca have dropped more points at this stage of the season than at any other time under Pep Guardiola. They’ve had issues with injuries, sharpness, fitness, team shape and – perhaps most importantly – intensity.

But then, out of that, there’s a curious momentum to this game. Real are the form team and also desperate for revenge after that 5-0 and so many Barcelona trophies. But it’s the Catalans who desperately need to win.

The decisive factor tonight could be whether Barca can raise their game to Real’s recent level. And, to be fair, they’ve done it many times in the past: not least int he 2009-10 Champions League group stage when, after a poor run of form and without Leo Messi, they lifted themselves to dismantle Inter and ease themselves into the knock-out stages after it began to look in doubt.

It’s hard to bet against Real on form. But, equally, you’d be a fool to bet against this Barca.

20.35 – Perhaps best illustrating how Guardiola wants to revert to previous brilliance, he’s switched from this season’s 3-4-3 to their regular 4-3-3 which has routed so many teams – including Real.

21.37 – Without wishing to get into the same old debate, this game so far has crystallised difference between Messi and Ronaldo.

Ronaldo could have killed game by squaring for Di Maria at 1-0.

Messi forces equaliser by passing for Alexis.

Different situation, of course, but same old story.

21.45 – Messi very lucky there! The number-10 – who has just been booked – goes in hard on Alonso. The referee goes to take out a yellow only to realise he’d just given one to Messi.

21.58 – Major first-half talking points:

• Real will have to score early in the first because, on the evidence of the first, they look a lesser team than Barca once their hugely impressive early pressing inevitably wears off
• In the context of recent officiating in Clasicos, Messi is lucky to be on the pitch after two bookable challenges following his first yellow. But, in the wider context, the referee showed common sense.
• On that, though, no doubt about the winner of the ever-present personal duel so far. Messi has completely driven Barcelona and set up the goal with a sublime pass. Ronaldo has been largely absent but could have killed the game by squaring to Di Maria… only to selfishly shoot.
• Alexis’s superb goal had a massive effect on Barca, as they looked a different – and much better – team after it. Confidence was surging through them after an error-strewn first 20.

22.20 – Alexis forces a fine save from Casillas after a divine Messi slide-rule pass. Barca well in control now and Real reduced to aggressive tackles.

22.33 – Should have been four for Barca. Another fine cross from Alves, Xavi fluffs it. This is like a training exercise at the moment.

22.37 – Keita comes on for Fabregas.