We have become used to seeing Laura Muir curled up in the foetal position after a desperate last-lap charge, her body drained of petrol and puff. But not, usually, after she has finished seventh in a heat. However this was the 5,000m, a distance she has run only once all year, so she was understandably relieved just to squeeze into Sunday’s final as a fastest loser.

“I ran as hard as I could,” said Muir, who took more than a minute to rise to her feet after crossing the line in 14min 59.34sec, nearly three seconds behind the Kenyan Hellen Obiri. “That was fast. I’ve been looking at the times of 5,000m heats from previous championships and that’s the fastest ever.”

The 24-year-old said she had put the ghosts of Monday’s 1500m final, where she missed out on a bronze medal by 0.07sec, behind her. But, on this evidence, her legs are still haunted by the extreme effort she put them through, particularly on a brutal last lap.

“I took a day to think about the 1500m and after that put it behind me,” Muir said. “I watched the race back, talked about it with my coach and my family, and it took about a day to analyse it all and put it into perspective. At the end of the day, fourth in the world is bloody good.

“It’s the best I’ve ever achieved in a global final. It’s better than seventh in Rio and the closest I’ve been to the front.

“So mentally I was very positive for this race. My body felt fine apart from that last lap. I have two or three days before the final so I should recover.”

And she has not ruled out an unlikely medal despite Obiri, the 10,000m gold medallist Almaz Ayana and the Dutch star Hassan Sifan being lined up against her. “I know I’m better than I ran and hopefully I can show it in the final,” she said. “Anything can happen.”

Muir will have the company of a fellow Scot, Eilish McColgan, in the final after she set a personal best of 15:00.38 in finishing fourth behind the Ethiopian Letesenbet Gidey, much to her surprise and delight.

“I’m so shocked with that time,” said McColgan, who judged her race perfectly and had plenty of kick left at the finish. “It was so slow at the start. We are not allowed to see the previous race so we were jumping over trying to see the time anytime the door opened. So we knew it was quick, the fastest losers’ spots were crazy.

“For me, usually 15 minutes over 5,000m has my eyeballs out from the start. I’m over the moon with that, I’m really, really happy. I felt like I wanted to push the pace a little bit to at least string it out because my mum said don’t turn it into to a 200m mad sprint – and that’s exactly what ended up happening. I couldn’t have asked for any more – automatic qualification and a new personal best.”

However Britain’s third athlete in the 5,000m, Steph Twell, looked well below her best in finishing 15th in McColgan’s heat in a modest 15:41.29.

“It wasn’t me out there,” she said. “I just couldn’t respond. My body didn’t quite feel right, so I’m absolutely disappointed, but it was an awesome experience. I was trying not to think about the race too much, but at the same time enjoy it and try to keep pushing forward, but I just didn’t have it in me.”