Mboma, 18, and Niyonsaba have moved respectively down and up in distance due to World Athletics’ ruling on female athletes with naturally elevated testosterone levels.

With athletes in this category not able to contest distances between 400m and the mile, Mboma, who in June set a world under-20 400m record of 48.54sec, has concentrated on the 200 metres, winning Olympic silver behind Jamaica’s defending champion Elaine Thompson-Herah in Tokyo in a world under-20 record of 21.81 and adding the world under-20 title in Nairobi last month.

At tonight’s Ivo Van Damme Memorial meeting in a King Baudouin Stadium populated by fans after last year’s COVID-19 absences, she won on her Diamond League debut in 21.84sec from Jamaica’s Olympic 100m bronze medallist Shericka Jackson, who clocked 21.95, and Britain’s world 200m champion Dina Asher-Smith, whose season has been undermined by a severe hamstring injury, and who recorded a season’s best of 22.04.

Fourth place in 22.45 went to Sha'Carri Richardson, who lost the chance of taking up her place at the Olympics after testing positive for cannabis at the American trials, and finished a distant last in her return to post-Tokyo 2020 action over 100m at the Eugene Diamond League.

"It was my first Diamond League experience and to be able to win in such a strong field is great," said Mboma.

"It has been a very tough and busy season with the Olympics and the World Junior Championships, but I'm still in good shape.

"I ran almost a personal best today, so that pleases me. 

"I still have one race to go in Zurich and after that I will take some rest.

"Currently I'm focusing on the 200m, but I hope in future also to get faster at the 400m."

Niyonsaba, who produced the fifth-best women’s 3,000m time ever in winning at the Paris Diamond League on Saturday (August 28), managed another victorious flourish over 5,000m - the event in which she thought she had qualified for the Tokyo Olympic final only to be disqualified for stepping out of her lane.

The 28-year-old Rio 2016 800m silver medallist clocked a national record of 14min 25.34sec to earn a second successive narrow victory over the Ethiopian who chased her home in Paris, Ejgayehu Taye, who on this occasion recorded 14:25.63.

In their wake was Kenya’s double world champion and Tokyo 2020 silver medallist Hellen Obiri, who finished in 14:26.23 ahead of compatriot Margaret Kipkemboi, who recorded a personal best of 14:27.12.

In sixth place, Eilish McColgan was not far off the British record of 14:28:55 she set earlier this year, clocking 14:31.26.

"I still do not know if I like the long distance more than the 800m, but I love challenges," Niyonsaba said.

"I won't think too much about it because it is what it is.

"A good thing about it is that I have a lot to improve - I'm still learning and am sure that I can go a lot faster in the future."

Duplantis won the men’s pole vault with a first-time clearance of 5.91 metres, a height that proved too much for United States vaulter Chris Nilsen, the Olympic silver medallist, whose best was a first-time success at 5.85m.

Third place went to Nilsen’s compatriot KC Lightfoot, who has cleared 6.00m indoors this year, as he equalled his outdoor personal best of 5.85m.

A third-time clearance at his next height of 6.05m - his second-best vault of the year after the 6.10m he cleared in Hengelo on June 6 - earned the 21-year-old US-based Swede the third meeting record of the night, bettering his own mark of 6.00m.

And for the tenth competition this year the bar rose to 6.19m, a centimetre above the mark Duplantis set in Glasgow last year

Duplantis came close - but no cigar.

He will surely be over it soon.

The women’s high jump saw the three Tokyo 2020 medallists switching around in the placings once again.

Having won at the Lausanne Diamond League meeting on August 26, Olympic champion Mariya Lasitskene finished second in Paris last Saturday as Australia’s silver medallist Nicola McDermott won on countback having cleared 1.98m.

Tonight McDermott went over at 2.00m but had to be content with third place behind Lasitskene, who also cleared 2.00m but took second place on countback, and Ukraine’s 2019 world silver medallist and Tokyo 2020 bronze medallist Yaroslava Mahuchikh, who earned victory 2.02m – just two centimetres off her personal best.

Dutch phenomenon Sifan Hassan failed to improve upon her 2019 women’s mile record of 4min 12.33sec, but still won in style - and a meeting record of 4:14.74 at the end of a long season in which she has become Olympic 5,000 metres and 10,000m champion and 1500m bronze medallist.

Hassan, who will run the 1500m at the Diamond League Final in Zurich next week, was followed home by Axumawit Embaye of Ethiopia, who clocked 4:18.58 ahead of Australia’s Olympic 1500m finalist Linden Hall, who set an Oceania record of 4:21.38.

That was the second meeting record of the evening following the performance put on by Michael Cherry of the US.

The 26-year-old New Yorker, who won 4x400m relay gold at the Olympics, won the 400m in a personal best of 44.03sec from Grenada’s London 2012 champion Kirani James, who beat him to individual bronze in Tokyo by two hundredths of a second and clocked 44.51 tonight.

The men’s 100m final saw a US clean sweep as Tokyo 2020 silver medallist Fred Kerley won in 9.94sec ahead of American trials winner Trayvon Bromell, who clocked 9.97, and Tokyo 400m finalist Michael Norman, who finished in 9.98.

Natoya Goule of Jamaica won the final track event of the evening, the women’s 800m, in 1min 58.09sec from Tokyo 2020 silver medallist Keely Hodgkinson, who clocked 1:58.16, with her British team mate Jemma Reekie third in 1:58.77.

Nadine Visser of The Netherlands won the women’s 100m hurdles from Nigeria’s Tobi Amusan on a photo finish after both clocked 12.69sec.

Brazil’s 21-year-old Alison dos Santos, who set a South American record of 46.72sec in taking bronze in the men’s 400m hurdles Olympic final, won in 48.23 from Commonwealth champion Kyron McMaster of the British Virgin Islands, who clocked 48.31.

Australians Stewart McSweyn and Oliver Hoare took first and second place respectively in the men’s 1500m, clocking 3min 33.20sec and 3:33.79.

In Wednesday night’s (September 1) discus finals Sweden’s Olympic and world champion Daniel Ståhl was a clear winner, reaching 67.01 metres with his final-three effort, ahead of Jamaica’s Fedrick Dacres, who threw 61.75m, and Kristjan Čeh of Slovakia who failed to register a mark with his last effort.

Ståhl, who leads this year’s world rankings with 71.40m, had earlier thrown 69.31m.

In the women’s event, world champion Yaime Perez of Cuba threw 63.41 metres in the final three sequence to beat the Olympic champion, Valarie Allman of the US, who managed 63.38m.

Justice was served as Perez had earlier produced the best throw of the competition, 66.47m, while Allman had a best of 64.25m.

Croatia’s double Olympic champion Sandra Perković, who won under pressure in Paris with the third of the final-three attempts, failed to record a mark on this occasion and finished third despite reaching 65.14m earlier.