Instructed by Lester that “third is not an option”, their most recent outing saw them deliver a historic 400m one-two at the British Championships, where Laviai triumphed.

“It’s crazy how this indoor season has panned out,” says Laviai, sitting next to her sister on a video call from their Aarhus apartment. “We were training pretty hard until the end of January and had no idea what shape we were in.

“I didn’t plan to go all the way through the indoor season, because the 400m in the UK is so competitive, my main focus is on Olympic trials outdoors this summer.

“After I ran 51.1, I was sitting on a plane back to Denmark thinking ‘I don’t know if I’m making the right decision’. Every fibre of my being was telling me to go to the World Indoors.

“We still think I can go a lot faster so I don’t want to shy away from the possibility of a medal.”

Their achievement is all the more notable given they live with neurological auto-immune disease multiple sclerosis.

Diagnosed aged 13, Lina had kept the condition under control before a sudden flare-up on the eve of her World Championship debut in 2022 that prompted her to reveal her story publicly.

Laviai also has the disease but is yet to suffer major symptoms.

“We’re still deciding not to take medicine because we’re not sure of the side effects,” explains Laviai.

“We’ve always been pretty good with our diet and nutrition, but after Lina’s flare-up we’ve taken it even more seriously. So far it’s all gone well.”

This weekend’s World Indoor Championships remain part of their bigger picture.

Laviai hopes to make the 400m final that would stand her in good stead for an Olympic tilt this summer in Paris, where Lina aims to compete over 400m hurdles and join her sister in the 4x400m.

If they do stand on the relay podium together for the first time in Glasgow, Laviai says it will be a moment they have waited for their entire lives.

“We would definitely celebrate it greatly,” she says. “It would be huge.”