On the same track where he won a surprise world indoor 1500m title last year, the 19-year-old upstaged his 21-year-old compatriot Yomif Kejelcha, whose attempt on the world mark had been billed after coming within 0.01 second of El Guerrouj’s world mile mark in last week’s meeting at the Millrose Games in New York City. 

After tracking Kejelcha to the bell, at which point the older athlete gave one tell-tale look backwards, Tefera moved past him on the outside before finishing comfortably clear in 3min 31.04sec, 0.14 seconds inside El Guerrouj's 22-year-old record. 

So far, so fantastic. But it was Tefera’s immediate reaction - or apparent lack of it - that caught the attention of numerous observers. Steve Cram, commentating for BBC TV, hazarded a guess that Tefera was not immediately aware he had broken the record.

After glancing down at the digital clock, he slowed to a walk, his face entirely impassive. "He looks as if he couldn’t care less," said Cram, incredulously. "Tefera is thinking, 'What’s all the fuss about? I’ve just beaten Kejelcha'. Come on, give us a smile!"

Tefera’s later comment - "I can't believe that. I’m delighted with the outcome and to have the world record is a special feeling" - contained some of the enthusiasm one might have expected to see at or close to the finishing line. Does it matter?

It certainly mattered to another frequent television commentator, Eurosport’s Tim Hutchings, the former world cross country, European and Commonwealth medallist who finished fourth in the 1984 Olympic 5,000m.

"Fab WR by Tefera," Hutchings tweeted. "But as Crammy pointed out politely on BBC, zero awareness of what he’d achieved. As @sebcoe mentioned recently, the athletes need to connect with the fans. Sadly, no smile (even at the win?) no celebration, nothing #LostOpportunity #Teach".

Hutchings added: "Kejelcha would have danced an entire lap. No personal criticism of Tefera, but he's an @iaaforg World Indoor Champion? Where was the joy? #Teach".

Jeroen Deen, a physiotherapist who works regularly with Ethiopian athletes, responded: "Why is the standard of celebration and giving interviews set by western commercial laws? Knowing Samuel he was overjoyed, but also good friend to Yomif, out of respect you keep it down, like a transferred soccer player scoring against his old club..."

The soccer note is presumably referencing Kejelcha’s move last year to work with Alberto Salazar as part of the Nike Oregon Project. 

It’s an interesting parallel to a recognised if unspoken code that exists in football. This had its most memorable example back in 1974 when Denis Law, that most excitable of players, produced absolutely no reaction after back-heeling a goal for Manchester City against Manchester United, for whom he had had many glorious years, and who were doomed for relegation.

To be honest, it is sometimes difficult to understand some of the emotional dynamics that exist between Ethiopian runners.

On the eve of the International Association of Athletics Federations (IAAF) Athlete of the Year Awards in Monaco at the end of last year I asked another young and extraordinarily talented Ethiopian athlete, Selemon Barega, whether he had any hard feelings about Kejelcha, who had blatantly hauled him to the ground as he moved past him in the final straight of the 5,000m at the IAAF Diamond League meeting in Lausanne.

Barega, already world junior 5,000m champion and world indoor 3,000m silver medallist behind Kejelcha at the age of 18, would go on to win the 2018 IAAF Diamond League 5,000m title in Brussels in a Diamond League record of 12:43.02.

The immediate reaction had been one of anger as he remonstrated with and pushed his older rival. But in Monaco Barega told me, with a little smile, that Kejelcha was his friend and that he had forgiven him.

"He told me that it was not on purpose and that he was just trying to grab what he could to survive from the fall," he said.

Getting back to Tefera - one hugely experienced observer of the sport noted that he was "completely spent" by the efforts he had just put in on the track.

But should he still have shown more emotion? It’s an emotive issue, for sure.

Personally I hate the obligatory knee-sliding celebrations of many footballers after scoring goals. I also disliked the kind of pre-arranged, orchestrated and crowing celebrations put together by, for instance, victorious United States sprint relay teams in years past. Personally I prefer to see whatever naturally occurs - even if that is not a wide smile.

The classic example occurred at last year’s European Athletics Championships in Berlin where Russia’s double world high jump champion Mariya Lasitskene added European gold to the silver she had won four years earlier - and could not have looked less happy about it.

The Authorised Neutral Athlete won on countback from Bulgaria’s Mirela Demireva, who had gambled on passing at 1.96 metres and 1.98m, during which heights all other opposition disappeared, and returned to match Lasitskene’s clearance of 2.00m, equalling her personal best, at her third attempt.

But there were no celebrations for the new champion, whose face was dark as she resumed her seat, punching the canopy alongside it before flinging down her bag and slumping in her seat with head in hands

"I won but I am upset," Lasitskene said.

"We expected much better jumps and much higher result.

"If you want to congratulate me, it is okay, but I cannot celebrate after this event,"

That reaction drew widespread criticism. It was certainly hard to recall a more disgruntled winner of a major gold. It was hard not to think - if this is what’s she’s like when she wins, what can she be like when she loses?

But that frankly frowning figure is not who Lasitskene mostly is. At Diamond League events over the past two years, at pre-programme press conferences, she always seems to have a smile hovering, and when she does let that smile arrive it’s broad and genuine.

I put the question of the non-smiling win to her in Zurich last September ahead of the first of the IAAF Diamond League finals.

"As you can see," she replied, "in my life I am not so serious, I can laugh and I enjoy life. But when I come to compete I become very serious, and I am thinking only about jumps, and concentrating on that.

"You talk about what happened in Berlin - that I was not happy to win with 2.00 metres. All the best jumpers came to compete in Berlin. I wanted to show my best result, but it was not correct for me."

Earlier, she had commented: "My motivation is always to jump higher than I have. Maybe it looks easy when I jump 2.00 metres, but it is not like that. It is a really hard job, but I like it."

Can you really argue with that?

Liam Morgan will appear on Thursday