The bloke in the crowd said it best, until Pep Guardiola said it better. In the midst of the noise around the Romareda, a collective murmur of incredulity, came a short and simple phrase that was just about audible and elicited the highest eulogy. It was March, a decade ago, and Lionel Messi had just scored his third goal against Real Zaragoza when, behind the Barcelona bench, someone in the stands spat out an expletive in disbelief. Guardiola heard it, turned and grinned, leaning on the bench as if he were at the bar. "Yep," he agreed, "if it wasn't for Messi, I'd be coaching in the second division."

Instead, he was a treble winner. As for Messi, he was already the best player in the world, maybe ever. Ten years on, remarkably, he still is. The best I ever have seen and ever will see, Guardiola had repeatedly said. And however much the coach presented himself as nothing more than the fortunate beneficiary of genius, that was partly his doing. Together they built arguably the finest team there has been, and made of him the finest footballer.

Which is why, nostalgia gripping and time running out, eight years since they parted company and five years since he last won the European Cup, Messi picked up the phone and dialed Guardiola's number.

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It is why Guardiola, who still hasn't worked with a player like him or won the Champions League since they were together at Wembley in 2011, replied that if his desire to play for Man City was real, he would try to make it happen. He had always insisted that he wanted Messi to stay at Barcelona, but if Messi was determined to depart, that was different. So Guardiola put the phone down and went to do just that.

Time will tell whether it happens, but there are plenty of reasons to try. Not least the memories of who they were and the hope that they might be again. Of how happy they were and how much they achieved.

Not so long ago, Guardiola told Catalunya Radio about discovering Messi. "Someone in the youth system told me there was one [lad] who was very good. He was very small, but he dribbled well and scored lots of goals," he recalled. The first time he saw him in the flesh was, by chance, in a shop at El Prat airport. "Small, shy," Guardiola remembered wondering if this kid could really be as good as they say. He soon found out that, no, he could be better.

"I saw him [play] in person and thought, 'With this guy, we'll win it all,'" Guardiola said. And that was pretty much what happened.

Together, they collected 14 trophies in four years, the last of them the Copa del Rey at the Vicente Calderón in May 2012. Messi scored that night, just as he scored in the two European Cup finals they won. That final season, he scored 50 league goals.

Fifty. He never scored as many in a season again.

They were so good against Manchester United in 2011 that in the final minutes, one opponent pleaded mercy. They beat Madrid 6-2 and 5-0. One night building up to the first of those Madrid games, away at the Bernabéu, Guardiola had an idea. It was late, but he phoned Messi and asked him to come to the training ground so he could explain what a false nine was. Guardiola built a structure and Messi made sure it worked. Football was never the same again.

In 2012, Guardiola was gone. Uneasy with the same regime that has ultimately presided over Messi wanting to depart, and over the steady catastrophic decline of the club, Guardiola was tired and burnt out. And so were the players. Things weren't right; there was tension, the relationship not ruined but frayed around the edges. As Dani Alves puts it in the documentary "Take The Ball Pass The Ball," where once he would have thrown himself from the top of the stands for his coach, he wouldn't be volunteering to climb to such a height any more.

When he left, Guardiola said that he had to go or else they would end up hurting one another. Better to have a clean break, and "break" was the word. It felt like something had ended, with many players looking lost in that farewell news conference, some of them aware of what they were about to lose. Perhaps aware, too, that they hadn't realised until it was too late. Messi didn't come, seen by some as evidence that his relationship with Guardiola had soured, but something he later justified by saying he didn't want his emotion exposed, sitting in front of the cameras.

All that worries me about Messi is him being happy, Guardiola had said once. It was a measure of how important Messi was, a player to build a team around, and it was worth it. "Is there a player more complete than Messi?" he once asked. "It is not about goals. Messi is the most complete player in the world. He can do everything: he associates with his teammates, he combines, he opens up space." Over the years he evolved. There have been many stages of Messi. But it all starts there, with that idea, born of the recognition and celebration of a generational talent.

In the beginning, Guardiola had defied the Barcelona board and a legal ruling to fight Messi's corner. Barcelona had gone to court to take on the Argentinian FA because they wanted to avoid losing Messi during the 2008 Olympics. But Guardiola saw how important it was to Messi and, despite Barça winning the case, told him to go to the Games anyway. Messi came back with a gold medal and grateful. Guardiola had won him over, for a time at least.

It wasn't always easy; Messi wasn't always easy. The men who have followed Guardiola can vouch for that. Hyper-competitive, more than people sometimes realise because they see someone for whom it all looks effortless, he could be sensitive too. There might be flashes of anger, not always well-articulated or easy to interpret, but they were there, and they weighed heavily on everyone. The rest of the players had to be good enough, even while no one can be that good.

Extremely demanding, Messi could be withdrawn, a look sometimes enough. Around him, people tried to second-guess him and follow what they thought he meant. The culture of the club became increasingly conditioned by him -- and all the more so in recent years. Guardiola made sense of it, or tried to, striking a balance. That wasn't easy either. In his book on Messi, Sebastian Fest claims that one day during Zlatan Ibrahimovic's first few weeks at the club in 2009, Messi sent Guardiola, sitting at the front of the team bus, a text message from the back. The message ran something along the lines of: I can see I'm no longer important for the team, so...

But it was Guardiola who went, leaving Messi behind as he headed to Bayern. The relationship was over, and it had seen better days. But there was of course respect and recognition, which would grow with the distance and the passing seasons. Guardiola spoke highly, warmly of Messi every chance he got; Messi rarely spoke at all.

Actually, though, it was not really something Guardiola said that best expressed just how good Messi was, aware that words would always fall short. "Don't try to explain him, don't try to write about him; just watch him," he said once -- and so he did. Sitting in the stand at the Camp Nou in 2015, just a fan alongside his dad and one of his assistant coaches, Manuel Estiarte, one night, he watched Messi nutmeg James Milner, drawing an astounded, tickled "ohh" from the crowd. Few know Messi better, but even Guardiola was taken aback by this: cameras caught him blowing out his cheeks and burying his face in his hands laughing at the absurdity of it all, his father cracking up alongside him. A seasoned football manager, a serial winner who had seen it all was giddy at the silliness of it, as Estiarte's mouth hung open and Milner sat on the turf.

Not long after, in 2015, the two men faced each other in the Champions League when Bayern drew Barca. "We've not spoken since [he left]," Messi admitted on the eve of the game, quickly correcting himself to say: "Ah, yes, we came across each other at the Ballon d'Or, but all we did was say hello and apart from that we haven't. We had a good relationship when he was here, but [nothing] since then."

Asked about his former player and what plans he had to prevent him beating Bayern, Guardiola said: "You can't stop him. If he is what he is, if he plays as he can, you can't stop him. You can't defend against talent of that magnitude. Teams have tried a thousand ways of stopping him, and it makes no difference. We have to make sure he does not get the ball, close his way to goal. But there is no defensive system that can stop him, and no coach either."

The following night, he was proven right. Messi did Messi things, famously leaving Jerome Boateng tumbling to the turf. A couple of months later, he was European champion again and Guardiola was not. Neither of them have been since then, and yet both have been recognised as the world's best for much of the time since, even if neither reached quite the same heights without the other. If at first Messi might not have thought he would miss Guardiola as much as Guardiola said he missed him, recognition could only increase with absence and time, the difficulties in replicating those successes: the good memories further away but far from extinguished, the bad ones fading from view, eclipsed by the excellence they had achieved.

Messi once called Guardiola the "best teacher," something he would be more aware of as others came and went, unable to control the class or get results from them. Guardiola watched Messi do things no one else could. Better than anyone else, he understood too why Messi couldn't do more. Nothing compared to Messi, Guardiola knew. Nothing compared to Guardiola, Messi knew -- a realisation that built with the passage of time, which was swiftly running out, and crystallised with European elimination.

A mutual need emerged. It hadn't always been there, or at least they had not always been conscious of it -- Messi hadn't, anyway -- but now they were. And once the idea formed, it could not simply be dismissed. How could they not want to work together again? How could they not recall better times, long for them? Guardiola and Messi were the making of each other; why wouldn't they reach for a second chance, give it another go?

Out of the Champions League again, head bowed, ashamed and humiliated, Messi turned for help. Freed from Barcelona, with some of the burden lifted, he can start again, lessons learnt and context changed, a point to prove and to drive him. Under pressure, sure, but without sole responsibility and with a coach he knows can guide him, one he'll listen to and take advice from perhaps more now than ever before. A coach good enough, whom he trusts to fix this, a man who will embrace him, understand and care for him, as he always has. One who will make demands too, bringing the best from that tiny, timid kid he first saw almost 20 years ago. He realises, if belatedly, that these are the safest hands in which to place his final years, aware that beyond that there is nothing.

Lionel Messi couldn't let his career end like this, and nor could Pep Guardiola.