At some point on Tuesday night the home fans at Old Trafford will probably sing a round of Viva Ronaldo. From distant metro platforms to wind-raked terraces, it has been a Manchester United standard of the past decade, an Elvis riff on those six years when Cristiano Ronaldo transformed himself from dazzling gadfly to the best footballer in the world.

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With Ronaldo back in Manchester Viva Ronaldo feels particularly apt, a song about a moment in time and a player that have both decisively passed. Juventus against Manchester United in Group H of the Champions League hardly needs the added soap opera of a personal homecoming. But the fact that it is Ronaldo’s first return of the post‑Ferguson years sees him a much-changed figure, in more ways than one.

In outline Ronaldo is a very different kind of athlete to the dandyish kid of the twirling, dancing Vegas years. In recent times Ronaldo has been defined by high‑spec efficiency, the purity of his numbers. Beyond this, Ronaldo returns to Manchester under his own disturbing cloud, the rape and assault allegations from 2009 that are the subject of both a criminal investigation and a civil suit.

Ronaldo vigorously denies any wrongdoing. But in the past week the faultlines have begun to tremble a little. Nike is said to be “concerned” about its $1bn Ronaldo‑centered sponsorship deal. As a lever designed to propel Juventus up into the real global A-list, both on and off the pitch, he has begun to look less certain, a little less unassailable.

At the end of which, Vegas‑era Ronaldo is more than ever an exhibit, mummified in YouTube clips, preserved in a song that is as much about lost glories and eras passing, a kind of sadness for United’s own best times.

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There are a couple of elements of Ronaldo 1.0 that seem more vivid now. First, it is easy to forget quite how good and how perfectly realised that Ronaldo was in his final year at United. And to wonder also what might have happened to that expressive, physically inventive wide forward had he continued to develop that way.

The following year, his first in Madrid, Ronaldo began to concentrate his powers, to became a more dazzlingly efficient footballer, a machine for winning. As early as 2009-10, a third of his goals came from the centre-forward position. Whereas the 23‑year‑old Ronaldo was the final form of something else, a player that was in many ways more captivating.

It is easy to forget quite how good and how perfectly realised Ronaldo was in his final year at United

Not to mention still the greatest the Premier League has seen. It is worth restating this. In October 2008 Ronaldo was five weeks away from his first Ballon d’Or, which he would win ahead of Lionel Messi, Fernando Torres and – in an impressive 12th place – Emmanuel Adebayor of Arsenal.

By the turn of the year, Ronaldo was the best player in a team who had just won the Champions League. Not to mention he was Ballon d’Or winner, Fifa world player of the year, PFA player of the year, Fifpro world player of the year, Uefa club player of the year, World Soccer player of the year, European golden boot and Premier League and Champions League top‑goalscorer. All of which, aged 23, puts Mo Salah’s lone stellar season into perspective, or Harry Kane’s extended peak, or the excellent form of Eden Hazard. They’re all very good. But this is genius-level stuff.

It was also Ronaldo’s exit season. His last game was the defeat against Barcelona in the Champions League final. Watching him walk off at the end in Rome you knew he was done. And received opinion would suggest Ronaldo still had all his best times ahead of him, most obviously in the shape of four more Ballon d’Or gongs and four Champions League medals at Real Madrid. A less popular view is that in many ways, his most captivating incarnation was already done.

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Ronaldo scored 42 goals in 2007-08. Best of all he did it as a winger, or as an innovative inside forward. Look back at the footage now and this Vegas-era Ronaldo has an astonishing range of creative movement, an irresistible urge to improvise. He can dribble, feint, pass, manoeuvre his body into the strangest shapes, find passes and touches and flicks invisible to every other person playing or watching the same game. He scored neck‑wrenching power headers, long shots, breakaways, solo runs. He made Carles Puyol run five paces the wrong way at the Camp Nou with a weird, off-the-cuff shimmy of the hips. He kept making defenders collide, slide into each other, wrestle with thin air.

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If this Ronaldo still feels a little unreal as his first return since the Fergie years rolls around, it is tempting to wonder how things might have ended up had this version stuck around a little longer, been left to explore the full depth of his own more performative style. The debate over the best player of the modern era would seem a little less binary for a start, less a matter of controlled Terminator-style football versus the more ferretty, imaginative stylings of Messi.

As it is, Ronaldo will play his 11th game for Juventus on Tuesday night. A 1-1 draw at home against Genoa on Saturday is the only one they haven’t won, although Ronaldo did score. A similar result at Old Trafford would leave the group looking uncomfortably tight.

Until then, this still feels like a homecoming curiosity, a reminder of just how exhilarating that Ronaldo-as-Elvis footballer was; and a reminder too, whatever his ultimate destiny, of happier past associations for a player who was, in that three-year spell, the best the league has seen.