That was his 10th consecutive global title at 5,000 or 10,000m.

Sir Mo has now won an incredible four Olympic gold medals and six in the IAAF World Championships. 

He is, by some distance, statistically, the most successful British athlete of all-time.

It was another tactical masterclass from Sir Mo, accelerating away again in the final 400 metres from the phalanx of Africans who had spent 24 laps trying unsuccessfully to break him, to revive memories of London 2012. 

Why then, do I feel more warmth towards Dwain Chambers, who chose yesterday to announce his formal retirement at the age of 39 from a sport that 14 years ago he so disgraced, than Sir Mo?

As the journalist who in 2003 exclusively exposed Chambers as a drugs cheat, you might have thought that I would be the last person to have admiration for him.  

But Chambers is surely unique among athletes who have tested positive for drugs that no-one in the sport has a bad word to say about him.

From the moment Chambers, who at the time was the European 100m champion, was told that he had tested positive for a cocktail of banned drugs he refused to adopt the usual approach of "deny, deny, deny". 

In fact, I am told that when Chambers received the telephone call he must have been fearing from the time he popped his first pill, his response was: "Oh well, shit happens".

He never tried to cover up what he had done, cooperated fully with investigators and, after completing his two-year suspension, became a powerful advocate for drug-free sport. 

The Londoner was targeted by the IAAF and UK Athletics with a spite never seen before. 

As well as being banned from the Olympics and stripped of the medals he won, Chambers was also barred from taking part in international events until he had returned prize money won during the period he admitted taking drugs.

UK Athletics chief executive Niels de Vos even urged British spectators to boo him on his return to the track.

They responded by cheering him - loudly - which was in stark contrast to the reception that Justin Gatlin received here tonight in the opening round of the 100m. 

Boos rung round the Stadium before and after the race for the American who has served two doping bans during his career.

Through it all, Chambers kept his head down, trained hard, ran reasonably fast again - winning the gold medal at the 2010 IAAF World Indoor Championships - and represented Team GB at London 2012 after a rule preventing convicted drugs cheats representing British was lifted following a legal challenge (not by him). 

Still, it does not matter how well Chambers turned his life round and became a powerful force for good, he knows that he will never receive a letter inviting him to Buckingham Palace for a tap on the shoulder. 

Farah, on the other hand, has already received a knighthood. 

The problem for the Palace is going to be how to mark Sir Mo's career when he finally retires.

His run of domination in the 5,000m and 10,000m is unprecedented - it eclipses anything Zatopek, Viren, Gebrselassie or Bekele achieved.

Somehow, though, I doubt in years to come Sir Mo's name will be mentioned in the same breath as Zatopek or Gebrselassie. 

Why?

I was discussing this earlier today with my colleague Nick Butler.

He believes many people's antipathy in Britain towards Sir Mo is because he was born in Somalia and is not considered "home-grown" in the way that, say, someone like Dame Jessica Ennis-Hill is. 

I do not buy into that theory as his athletics career as a runner started as a teenager when he used to take part in cross-country races as a youngster in London. 

Sir Mo is just as much a product of the British club system as Dame Jessica.

Or at least he was until he was 26. 

That is when he left Britain to live in the United States and be coached by American Alberto Salazar, the former winner of the Boston and New York City Marathons. 

Since then, the titles won by Sir Mo have grown. 

But so have the doubts.

For a man who has never failed a test and for who there is no evidence of ever having taken anything illegal, the continued necessity of having to defend himself must have become wearisome.

It is no surprise that, in the build-up to these Championships, Sir Mo has refused to face the British media. 

Or that Salazar declined to travel here to support his runner. 

The questions may not have been asked but that does not mean they have gone away. 

Salazar continues to be the subject of an investigation by the United States Anti-Doping Agency and, in a report leaked by the Russian cyber hackers Fancy Bears' that he administered medication to his athletes, including Sir Mo, that they did not need, although there is no suggestion that anything illegal occurred. 

Then there are the links to Jama Aden, the Somali coach arrested by Spanish police on doping charges, who British Athletics used as an "unofficial facilitator" for a training trip Sir Mo made to Ethiopia in 2015. 

In the meantime, Sir Mo has gone from a runner who failed to reach the final of the 5,000m at the 2008 Olympics in Beijing to one now unbeatable.

Sir Mo won his first World Championships title in 2011 at the age of 28 and, having turned 34, he will challenge for his last in the 5,000m in these Championships next week before retiring from the track. 

Few believe he will be beaten and not win an incredible 11th consecutive major global championships title. 

History has judged Dwain Chambers kindly.

It will be interesting to see how it treats Sir Mo.