However, his victory was almost a footnote after an extraordinary incident on the final bend between the two young Ethiopians who had been contesting the lead, 20-year-old Yomif Kejelcha and his 18-year-old compatriot Selemon Barega.

The older runner, who had burst past Barega into the lead at the bell, began stumbling as they approached the final straight, but as he fell he grabbed hold of his younger colleague's shorts and dragged him out into lane three. 

It was almost as if he was saying to Barega: "If I can't beat you, at least I can stop you winning".

After Balew, who had followed Barega home in the last Diamond League 5,000m, had cruised past, Barega recovered himself to finish second in, astonishingly, a season's best of 13:02.67.

But he was anything but a happy athlete at the end, raging and gesturing at his fellow Ethiopian when he finally picked himself up and arrived, sheepishly, at the finish area.

For a moment it was as if we had been watching something out of one of the more acrimonious FIFA World Cup matches. 

In athletics terms it called to mind the experience of Ethiopia's most illustrious runner, Haile Gebrselassie, who was punched in the back of the head by Kenya's Josphat Machuka as he overtook him to win the world junior 10,000m title in 1992.

Doubtless Gebrselassie, now President of the Ethiopian Athletics Federation, will be making his views on the incident known.

In the final event of the programme, Noah Lyles offered another fluent demonstration that he could be the next big thing in the men's sprints as he equalled his 2018 world-leading time and personal best of 19.69sec to win a 200m stacked with talent.

It was another hugely talented United States athlete, Michael Norman - who won last month's NCAA 400m title in a 2018 world-leading 43.61 and followed up with a 200m victory in Paris last Saturday (June 30) in 19.84 - who led into the final straight, but Lyles moved smoothly past his right shoulder over the final 50m.

Norman clocked 19.88, with Ecuador's Alex Quinonez third in 20.08, one place ahead of Norman's University of Southern California team-mate Rai Benjamin, winner of his own NCAA title over 400m hurdles in 47.02, who clocked 20.16.

After doing a no doubt carefully choreographed dance of celebration, Lyles pronounced himself "very pleased" to have matched his best time, although he added: "It could have been faster".

Qatar's Abderrahman Samba, who announced yesterday that this would be his last Diamond League race of the season, duly secured a sixth 400m hurdles victory in the competition in what is now his familiar style, finishing strongly to overhaul Norway's fast-starting world champion Karsten Warholm over the final two flights of hurdles before crossing in 47.42.

Warholm - who would be having a great season were it not for the eruption of this fellow 22-year-old former Mauritanian - took second place in 47.94, ahead of Turkey's Yasmin Copello, who clocked 48.85.

For defending Diamond League champion Kyron McMaster of the British Virgin Islands, however, the night ended in disappointment as he was forced to slow to a halt halfway down the back straight.

"I am happy with my fitness at the moment," said Samba. 

"I want to break the world record. 

"Now whether it will happen this year or in the coming ones is hard to say. 

"The objective of the season for me is the Asian Games which will take place at the end of August."

Sergey Shubenkov, a frustrated figure at the last IAAF Diamond League meeting in Paris after being disqualified from the 110m hurdles for false-starting, experienced emotions at the other end of the spectrum tonight as he defeated the world and Olympic champion Omar McLeod to earn victory in 12.95 - his second fastest time ever.

The tall figure of Russia's Shubenkov, who preceded the compact Jamaican as world champion and took silver behind him in London last year, got away well, but there was little between the two figures as they ran shoulder-to-shoulder until McLeod landed awkwardly after the eighth flight of hurdles and lost his chances in a moment's stumble, slipping back to fifth in 13.41.

Shubenkov, operating here as an Authorised Neutral Athlete, maintained his form to earn a third successive sub-13 second race in three finals, having clocked 12.99 in Montreuil on June 19 and then, on Monday (July 2), finding the ideal way of getting over the disappointment of Saturday's Paris setback by setting a personal best of 12.92 in winning at the Istvan Gyulai Memorial meeting in Hungary.

A third European title is high in his ambitions this year - and as things stand it is hard to see anybody stopping him.

"This is what we train for," said Shubenkov.

"I am super-excited. 

"I have already run under 13 seconds three times this season, so that makes this my best season ever.

"Twenty-sixteen was a tough year when we didn't have much opportunity to compete but now competing with the best guys on the circuit is helping me improve my level."

Marie-Josee Ta Lou, silver medallist over 100m and 200m at last year's IAAF World Championships, has got into a winning habit this season and here she finished strongly in the shorter distance to take victory in 10.90 against a field that included Jamaica's Olympic 100m and 200m champion Elaine Thompson and the Dutch sprinter who beat her over the longer sprint in London, Dafne Schippers.

World and Olympic 800m champion Caster Semenya had elected to run over 1,500m here, but for once she did not earn that winning feeling at the end of the night as she eventually finished sixth in 4:00.44sec in a hugely fluctuating race which eventually saw Shelby Houlihan of the US sprint past Britain's Laura Muir in the final 50m to win in a personal best and meeting record of 3:57.34.

Germany's Malaika Mihambo earned a dramatic victory in the women's long jump as, with her last effort, she matched the lead of 6.90m that Olympic bronze medallist Ivana Spanovic had established with her first effort, winning by virtue of a better second jump - which, at 6.70m, was just three centimetres farther than the Serbian's second best.