Farewell then, project superstar. By the end of this Champions League semi-final second leg it seemed oddly fitting that the final act across 180 minutes should be Kylian Mbappé falling over his own feet.

Mbappé was through on goal at the time, the most beautifully balanced footballer on the planet haring away from a clutch of yellow shirts in emergency battery mode, then slipping over on the Parc des Princes turf just as the final whistle was blown.

This, then, would be the final act of Mbappé’s final European game in Paris, and by extension the last significant note of six years as the sun king of the Qatari sport project.

A 2-0 aggregate defeat by the fifth-best team in Germany has its own kind of poetry, its own kind of bathos. But Dortmund were also magnificent here, defending for the final half-hour like men tied together on the deck of a sinking ship, and entirely deserving of another Wembley final in this competition.

They were lucky too. Paris hit the bar and the post four times. But they were also oddly under-stretched, waiting to be dragged into those terrible places Mbappé will take you, but never quite getting there.

Instead Mbappé spent long periods moving around the edges of this game, glimpsed vaguely through the blur of other people playing football. Paris had been a lovely soft mild place on Tuesday afternoon, the Parc surrounded by pyro-wielding hordes hours before kick-off, and the noise inside relentless from the stand occupied by its ultras.

But by the end here it was hard to avoid a sense that the entire game in between embodied the colder, stranger elements of Mbappé’s PSG career. Magnificent staging. Fawningly overwrought buildup. Cinematic moments, regal closeups. For 90 minutes talent existed on a pitch, decoratively. But for Mbappé, things just kept on not happening.

He was genuinely poor in the opening half-hour. “I don’t want the striker to go and get the ball in midfield, but to touch it in the decisive zones,” Luis Enrique had said on the eve of this game. Luis, you’re probably safe old bean.

Instead Mbappé skulked. He fell over quite a lot. He completed four passes. He moved laterally. He gestured and pointed and seemed to be definitely in charge of the spectacle around him, just unable to affect it.

After the half-hour mark something began to stir. Mbappé finally engaged the afterburners, gliding inside from the left. He has such an easy grace when he starts to move like this, with so much more twang and snap in his movements than any other human in his orbit, but also with his head always up, brain whirring, doing the maths, finding angles, making up a story as he goes.

Otherwise there was a sense here of trapped energy, of a grand talent struggling to find its own edges. Borussia Dortmund are fifth in the Bundesliga. Mbappé did nothing against them in both of these games. Is he the best player in the world? He has the most talent. He loves the big moments. But six years is a long time for anyone to spend in a place where the intensity levels come and go. Mbappé spent an hour here trying to remember himself.

He will now play one more game at the Parc des Princes before he leaves this summer, providing a bookend to these prolific, relentlessly lionised, oddly room-temperature years. Then again, he also might not.

The last time Mbappé started a game in Ligue 1 was five weeks ago. It has been not so much a long goodbye as a meandering, work from home kind of season’s end, extended scenes from Kylian Mbappé’s day off. Football is a long game. It’s about a sustained pitch of performance, dragging the moments out of yourself. Is this the way his talent is meant to be used?

Dortmund took the lead early in the second half though Mats Hummels, heading in direct from a corner. Paris had hit a post twice just before. It felt like a moment to press the gas, for Mbappé to pull himself right up to his full height. He moved into the centre with 63 minutes gone and it seemed as if this was it. These are the legacy moments.

It took him eight minutes to actually touch the ball. He hit the crossbar when he should have scored. The best players take these moments. Mbappé is the best player. What happened here exactly?

By the end, the question seemed to be: what was the point of spending seven years of his wonderful prime here in Paris? Extraordinary numbers in every competition. A recurrent drama of personality. But in the end, Mbappé’s legacy in Paris will be a €840m (£722m) annual turnover and the founding of a really excellent sporting brand.

He has been an easy sell too, a player so spectacular even people who don’t like football can see how good he is, can buy into that celebrity image. This is, though, still sport, with all its hard edges, its unforgiving light. Mbappé has been a star in Paris. The lesson from his final act is that in order to find that final level he needs a little more than football’s greatest, most stultifying case of project-ball.