James Lawton: Wondrous week that should restore our faith in the beautiful game
We fret over the future of football with almost neurotic compulsion, even to the point where sometimes we worry that it is on borrowed time. But then maybe we agonise too much.
Perhaps when we reel off such problems as raw greed, runaway cheating, brazen manipulation by agents, ego-crazed coaches and the declining status of the international game, we too easily lose sight of the one unchanging redemption.
It is that football remains the world's most popular game for two very good reasons.
No other can touch it for both its simplicity and its capacity to produce sublime individual expression.
Sceptical? You must have missed the Champions League action which this week carried us towards a climax which has the potential to grace any year, any epoch.
You must have missed Ronaldo's talent flying as high as his self-regard with a goal which, miracles of restoration apart, has surely broken the recently notable nerve of Juventus.
You couldn't have seen Jurgen Klopp's passionately committed Liverpool destroy some of the certainties of Premier League champions-elect Manchester City for the second time this season.
It may be true that, at the Camp Nou, Barcelona were less than imperious against a defensively inadequate Roma, but Lionel Messi and Andres Iniesta will be less anonymous when they appear in the semi-finals - a certain consequence, surely, of the 4-1 first-leg win.
And, who knows, Sevilla might find again in Munich the kind of spirit and touch which, speaking of ego-crazed coaches, brought down Jose Mourinho's United at Old Trafford.
Liverpool's ravaging of City coach Pep Guardiola's hopes of winning a third Champions League title has probably done little to subdue Mourinho's desire to sabotage a domestic title celebration after the Manchester derby at the Etihad Stadium tonight.
Then again, whatever happens, maybe even he will find it hard to deny that he was left behind in the week which reminded us so strongly of football's power to capture the imagination of its audience by the boldness of a perfectly prepared team.
Ronaldo's goal was no doubt the keynote - it re-conjured the most thrilling of football moments; it sent the pulse racing as did the one of a young Bobby Charlton when he watched another Real superstar, Alfredo di Stefano, mesmerise the Santiago Bernabeu stadium six decades earlier - but if you must pick the man who shaped the week, who made it glow so fiercely, it has to be Klopp.
Not for the first time in his career, but never more spectacularly, he achieved the fusion of a coach's best hopes and the execution of his team.
Liverpool found a will, a competitive hauteur, which marginalised, at times utterly, some of the finest players in Europe.
Yes, there are charges that, at critical moments, Klopp has lacked a Plan B - which is to say workable defensive resources - but against the likes of Kevin de Bruyne, David Silva and Leroy Sane his only regret was that in the second half the ferocity of intent which brought three goals before the break lessened in the cause of defensive security.
He says, beyond contradiction, that there is still vital work to do in the second leg but no one in all of football has more reason to carry a lighter heart than he does into his lunch-time immersion in the Merseyside derby.
He has fulfilled the most vital function defined by his great predecessor Bill Shankly - he has made his people happy, a number whom, given all of Klopp's instincts, will never include the morons who attacked the City team bus before kick-off.
That was hopefully an isolated return to some of football's, and Liverpool's, grimmest days and perhaps it was also a reminder of the game's power to survive the heaviest of burdens.
If it has been able to emerge, substantially at least, from the sickening, potentially death-dealing institution of football hooliganism, its current excesses and self-absorptions are certainly made to seem less terminal.
Why? Because, as this last week has so reassuringly proved, there is still a superb product to be found amid the chaos of self-indulgence and short-sightedness and general folly.
There may be legitimate complaints that the foreign transfer market has inhibited the development of national teams and created questions about the depth of the loyalties and commitments of many of the star imports - think Mesut Ozil on an off-day at the Emirates - but at Anfield this week you could not draw the thinnest line between the commitments of the playing squad which included - alongside five Englishmen and a Scot - two Dutchmen, a German, a Croatian, a Spaniard, a Senegalese, a Brazilian and the striker-pharaoh Mo Salah.
Here was unity of will on a football field to an extraordinary degree.
Certainly, it is not easy to believe that the stunned expression on the face of the great coach Guardiola will have disappeared completely when it comes time to shake hands with Mourinho this evening.
Guardiola's face spoke of bewilderment that his team could be so relentlessly harassed, that De Bruyne found himself looking to the sky for inspiration, and David Silva, the sharpest, most adept of movers, had to scuffle for inches of space where normally he sailed into so many yards of it.
When Eamon Dunphy questioned Guardiola's ability to win the greatest prizes without the help of such as Messi, Xavi and Iniesta, he was echoing the thoughts of none less than Alex Ferguson.
When Old Trafford's most successful manager had heard that Guardiola was planning to take a sabbatical in New York and leave Barcelona after they had trounced United in the Champions League final of 2011, he warned his young conqueror that sometimes in football you have moments, and resources, that may come only once even in the longest careers.
It is a possibility, it is fair to assume, that has occurred to Guardiola these last few days. For Klopp the speculation had to be rather more optimistic.
He could, after all, tell himself that if it was his week it also belonged to football, which sometimes is still a wondrous place where almost anything can happen.