The inquest into what went wrong for British Athletics is already live while the championships are still ongoing and Britain’s hunt for a second medal endures. But amid the gloom a few athletes have outperformed expectations, chief among them Dina Asher-Smith.

The 21-year-old broke a foot in February and the prognosis was grim, it being an injury that has taken other athletes as much as two years to recover from. A couple of weeks later she had an operation in which the fracture to the navicular bone was fixed with a screw. Six weeks was spent on crutches and she was not able to run in spikes again until June.

But her remarkable comeback continued as she ran a season’s best 22.73sec to qualify for the 200m final, finishing second in her semi-final. Asher-Smith rounded the bend together with eventual winner Marie-Josée Ta Lou, the Ivory Coast athlete who won 100m silver in the week and looked to be in medal-winning form again.

Before injury struck Britain’s fastest woman she would have hoped to win her first senior global medal in London and at the stadium where she carried kit during the 2012 Olympics. Injury caused a recalibration of expectations and she claimed in the buildup that she would be delighted simply to make the final. But this assured run suggested there could be more to come. “I’m absolutely over the moon, especially after the year I’ve had,” she said.

Caster Semenya remains hot favourite to win 800m gold after breezing into the semi-finals as scrutiny continues to be applied to her every performance at London 2017. The South African has not lost a two-lap race since 2015 and looked supremely comfortable, jogging through the line in 2min 1.33sec to win her heat. An outstanding athletic talent is beyond question but debate over Semenya’s participation at these championships intensified after she won 1500m bronze in the week, pipping Britain’s Laura Muir on the line. Her continued success here is undoubtedly awkward for the IAAF. Athletics’ world governing body is presently trying to implement a rule which in the future would force the 26-year-old to have hormone-replacement therapy or quit the sport.

Semenya, who has run 15 sub-two-minute 800m races in her career, is growing understandably weary of continued questioning about hyperandrogenism, the condition she has which is characterised by very high levels of naturally occurring testosterone. On Thursday night she conducted just one broadcast interview before departing the stadium to focus on preparing for the semi-finals.

She will be going for her third world title in London, having won in 2009 and 2011, with her biggest challenge likely to come from Burundi’s Olympic silver medallist Francine Niyonsaba, who was the fastest qualifier in 1:59.86.

They will be joined in the semi-finals by all three British 800m women, who safely advanced. Lynsey Sharp was the most assured of the trio, finishing second in her heat in 2:01.04, just behind Kenya’s Margaret Wambui.

At London 2012 Adelle Tracey lit the flame inside the Olympic Stadium as one of the secret seven, a group of youngsters plucked from local athletics clubs to carry out the task. Her fondness for this part of east London only increased as she qualified as a fastest loser with a personal best of 2:00.28.

The part-time make-up artist was overjoyed. “It’s like when you’re a kid and you just want lots of goes,” she said, “I’m so happy to get to have another go.” Shelayna Oskan-Clarke also advanced, finishing third in her heat in 2:01.30.

What difference a few days have made for Katarina Johnson-Thompson, who soared into the high jump final with a first-time clearance of 1.92m, banishing memories of the heptathlon where a best effort of 1.80m put paid to her medal hopes. “If you fall off a bike you’ve got to just get back on it straight away so that’s what I wanted to do,” said Johnson-Thompson, “I didn’t want to leave the stadium in those terms with the high jump so I’m glad I came back and proved to myself more than anyone it was a freak accident and I can jump.”

The 24-year-old will be joined in Saturday’s final by another multi-eventer Morgan Lake, who cleared 1.92m at the second time of asking.

Christian Taylor of the USA was bidding to break Jonathan Edwards’ world record of 18.29m in the triple jump, which has stood for 22 years. He did not come close to touching that mark but a 17.68m jump in the third round was enough to take a third world championships gold.

Kori Carter, also of the USA, won the women’s 400m hurdles in 53.07, with the British team captain Eilidh Doyle trailing home in eighth. “I took hurdle seven the wrong way and after that I was all over the place,” said Doyle. “If I had finished eighth and nailed the race I would’ve been happy but I feel I could have gone a lot faster out there.”