MADRID -- Well, that's the Zinedine Zidane honeymoon well and truly finished. It was ended by a historic stat, too: Barcelona have never before won three straight Liga clasicos at the Santiago Bernabeu. It was also ended, quite possibly, by the earliest in living memory that Madrid, in the calendar year before the title can actually be awarded, are out of the race to be champions.

But as someone who has continued to throw confetti and wished bountiful happiness upon the happy couple since the white wedding between Zizou and Madrid, let me also be honest enough to offer some marital advice. Yes, Zizou: it's often a good idea to spice up a marriage when you're getting to the second anniversary. You need to offer something new, something unexpected, something charming -- but it's supposed to be something daring. Something to take the breath away.

After Saturday's horrible defeat, Zidane said, "I know I'm going to get beaten up tomorrow [in the media] for the decision to start [Mateo] Kovacic ahead of Isco, but I'm never going to change. I'm here to make decisions, and if we'd scored in the first half, it would all have been different."

Well honestly, mon cher, that's not good enough.

The idea to spice things up by demoting the team's most appealing young talent, Isco, and then to confirm that the other alternatives adding fizz and bubbles to the relationship, Marco Asensio and Gareth Bale, would be beside him on the bench? That was a very weird concept and one that's hard to justify.

But -- and this is important -- it wasn't outright wrong.

Zidane had noticed how Ivan Rakitic was playing centrally recently, to great effect against Sporting Lisbon and Deportivo La Coruna, and he already knew that Lionel Messi is now a pocket-sized quarterback. The same guy who revolutionised European football in Spring 2009 by accepting Pep Guardiola's invitation to re-invent the "False 9" position by playing as the central striker, but in a gap between the midfield and the wingers, is now something else entirely.

It was Xavi who first identified that when he left the club, the most sensible option was to allow Messi to morph into his role: "Mavi," if you like. Zidane's concept of constructing a victory, which they absolutely needed to register if they were to be back in this title chase, was to first concentrate on nullifying the opposition's "appeal" -- it was a bit weird, a bit "un-Zizou" and -- a bit Jose Mourinho.

Mourinho also tried something reductive and conservative in 2011 when he paired Sergio Ramos and Raul Albiol at centre-back so that he could put Pepe as the "destroyer" in midfield alongside Xabi Alonso and Lass Diarra. The concept was to contain, frustrate and ensure that Madrid didn't concede.

And that plan went to pot.

Zinedine Zidane's hesitance in making some necessary changes was fatal in Saturday's significant defeat. OSCAR DEL POZO/AFP/Getty Images

As Zidane was mulling over giving the admittedly prodigious Kovacic his first Liga start of the entire season, and his first start of any kind for nearly three weeks, Mourinho's mistake should have been a Christmas parable. It should have made him hesitate and ultimately change his mind. But he'd seen signs of staleness in the relationship. He'd seen his team look complacent and flat in recent weeks; he wasn't falling out of love, but his unbridled confidence was being undermined just a little.

Clearly, Zidane's idea was to contain, try to take the sting out of the match -- perhaps even nicking a first-half goal, but Marc-Andre ter Stegen's terrific save from Cristiano Ronaldo, and CR7's inexplicable fresh-air swipe at the ball when it looked easier to score, didn't help him one iota.

Where Zidane gave an "assist" to Barcelona -- although perhaps not quite as devastating as the one Sergi Roberto gave to Luis Suarez for the opening goal -- was in not understanding that his idea wasn't working by half-time. It's also where he added fuel to the argument of those who feel that he's an inspirational man-manager and a terrific "player whisperer" but is not, by any stretch, as adept at strategy or tactics as he needs to be.

Given that this is still an extremely early stage of his coaching career, that's not an outright condemnation by any means. Although I don't think that even Zizou's biggest fans expect him to go on and rival Sir Alex Ferguson's record; just by means of comparison, when Fergie was two seasons into his first full-time managerial role at St. Mirren in 1976, he was still a year away from his first trophy, winning the second division in Scotland, and about 20 years away from being recognised as a major managerial presence.

So if Zidane occasionally looks raw, and if he sometimes shows a deficit in street-smarts or experience or tactical acuity, then I'd prefer if his judges were cautious instead of condemnatory.

But here's the cast-iron case against him this weekend, an important weekend at that. By half-time, it was patently evident that Barcelona were playing possum. They looked calm and conformable, they were making at least as many chances as Madrid, they didn't look in danger of feeling "under pressure" and it was just as obvious that Kovacic was tiring.

The shrewd play, the "Zidane moment" that would have given us, at least, a very different, more intricate and less clear-cut second half -- albeit that Barcelona may very well have won the same result -- would have been removing Kovacic and introducing at least one from Isco, Asensio or Bale, and probably two of the three.

Karim Benzema kept on taking up his traditionally good positions and then fluffing the killer pass. OK: his header off the post gave hope that maybe he had a special moment in him, but the game was largely passing him by, the crowd were on his back and the smart gamble would have been Bale for Benzema at half-time.

This isn't a retrospective idea formed after a 3-0 win for the Liga leaders -- and now, champions-elect -- this was screamingly evident at half-time. More so was the fact that Kovacic was running out of gas.

Cristiano Ronaldo and Real had no answer to Barcelona in the second half. Denis Doyle/Getty Images

One of the things that coaches and players teach you is that tiredness often doesn't hit a player first in the lungs or the legs, but the brain. When the opening (and most crucial) goal is scored, the young Croatia international makes a bad, bad choice.

Go back and watch him if you've recorded the match. Luka Modric fails his duty first, and that's the most important failure here. Sergio Busquets brilliantly cuts Toni Kroos out, and Rakitic anticipates that Barcelona are about to break the traps that have been set around him. He sprints, Busquets delivers the same little "shunt" pass with which he began the brilliant move via which Barcelona won the Clasico here at the Bernabeu last April.

Rakitic runs, Modric doesn't react, and suddenly Kovacic has a major choice. His head's telling him: attack the ball and close down Rakitic's run. He and Rakitic are international teammates. He knows only too well what the midfielder is capable of. He also knows that in almost any situation, the deal is that you attack the ball carrier: accept that moving off your man might leave you looking daft. But not as daft as when the team concedes a goal. Snuff out that moment of danger, and perhaps Madrid go on to win the Clasico via, you guessed it, Bale or Isco or Asensio.

Maybe, only maybe, but at least the idea is still in play.

Instead Kovacic looks over his shoulder, sees Messi and remembers the precise reason he's been picked: to close down Messi. He remembers the late, unmarked run that Messi made last April to score the winner, and so he chooses badly. He lets Rakitic run. He drifts off the important moment and stays "near" Messi.

An unencumbered Rakitic feeds Roberto down the right and the Catalan's pass to Suarez for the "goal that won La Liga" is a precise as it was last week, when he set up the Uruguay international against Deportivo La Coruna. And that was that.

Kovacic's plan to shadow Messi worked until the Croatia international got tired and switched off. Angel Martinez/Real Madrid via Getty Images

So here we rest. Zidane's original idea was perhaps a little faulty, but not completely wrong. It went against his character, against his trajectory as a footballer and against the Madrid tradition. But he had a chance, at half-time and with the evidence of the first half at his disposal, to correct the idea, to roll the dice and to try to use any or all of three players who have hugely damaged Barcelona in recent matches: Isco, Bale, Asensio. But he didn't.

Until now, Madrid's weak defence of their title has had many authors, most of them not their manager. There have been injuries, suspensions, subconscious lowering of intensity, and his major rivals keep on winning. But this time, dear Zizou, this time it's on you.

You made a big decision, fine. It went wrong, with mere mortals able to see it sooner than you did. And some of Barcelona's players, sharks that they are, smelled blood in the water.

Happy second anniversary when it comes in a few days' time. But the marriage, which has been so romantic up until now, needs to get back to what once was a perfect match.