There will be 60 players starting matches at the Stade de France this weekend across the two blockbuster Rugby World Cup quarter-finals between Ireland and New Zealand, and France and South Africa. Precisely one of them could be classified as a Test rookie – France winger Louis Bielle-Biarrey.

The Bordeaux flyer was still a teenager when he was included in France’s wider squad to start preparing for a World Cup on home soil, only turning 20 on June 16.

At that point, he and fellow age group star Emilien Gailleton felt like long shots to make France’s final 33, with the importance of cohesion and reps at the highest level increasingly invaluable in top-level rugby. That they had been withheld from France’s World Cup-winning U20s side felt more like a nod to their importance post-World Cup than their hopes of making the cut this time around.

After all, one of the abiding traits of Fabien Galthié’s period in charge of France has been his consistency of selection.

The young star keeps ball alive against Namibia (Getty Images)

And yet very quickly, the whispers started that Bielle-Biarrey was turning heads in training. His pace is frightening. You simply need to watch one of two tries he scored for France U20s against Wales in the Six Nations to realise, he looks like some sort of AI fake as he races at double the speed of everyone else on the field.

But of course, elite top-end speed is not enough. Bielle-Biarrey has an ability to read the game well beyond his years, and seems remarkably unfazed as he moves up each rung of the ladder at warp speed.

A product of the Grenoble academy – who have also brought the likes of Vincent Clerc and Ange Capuozzo through their ranks – Bielle-Biarrey headed west to Bordeaux in 2021.

His impact was immediate. Thrown in at 18 in a big European game against the Scarlets, where Bordeaux-Bègles found themselves decimated by injuries, Bielle-Biarrey shone, helping himself to a hat-trick and even knocking over a conversion for good measure (remember that if France against South Africa goes to penalties).

Related: What happens if there’s a draw in Rugby World Cup knockouts?

He played at full-back that day, and is comfortable across the back three.

That versatility has proven useful, but even so, the idea that he would be starting a World Cup knockout game without injuries seemed preposterous as recently as the start of August.

Then, Bielle-Biarrey was given his Test debut as a French second-string side headed to Edinburgh to take on Scotland in their first World Cup warm-up.

Bielle-Biarrey evades Italy (Getty Images)

Within the first 25 minutes, he had made one try and scored another. The French kids ended up losing, but again, the whispers started. He was moving ahead of Ethan Dumortier – who had started every game for France in the Six Nations – in the pecking order.

Now, cracking the final squad was starting to seem increasingly plausible. Bielle-Biarrey had jumped into the slot as the back-up wing behind Damian Penaud and Gabin Villière.

Still, could he break past one of the Grand Slam-winning pair? It seemed unlikely, but with Villière having spent the whole of last season on the sidelines with injury, he did not seem to have rediscovered his best form. A so-so performance in the win over New Zealand was followed by another underwhelming outing against Uruguay. Bielle-Biarrey, by contrast, took his opportunities in that game and earned greater trust from the coaches.

As Galthié and Co returned to their first-choice side for Namibia, Bielle-Biarrey was in. He notched two tries, including one long-range effort, added another fine finish against Italy in a must-win game for France and cemented his place in the top side.

When he was named to take on South Africa, the only surprise was the lack of shock at his inclusion.

After every game, the most notable thing about Bielle-Biarrey is how unfazed he seems to be. The stage keeps getting bigger but he does not worry.

Will that remain the case against the world champions at the Stade de France on Sunday? That is the question he still needs to answer.

But with five tries in six appearances for les Bleus, Bielle-Biarrey has answered every question asked of him so far.

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