On a night of perfect 10s for the irrepressible Usain Bolt, it took a hapless cameraman on a Segway to do what Justin Gatlin again failed to and bring him down.

If that was a comedic end to the second act of a rivalry styled as a modern morality play, for Bolt his stroll to an unprecedented fourth consecutive men’s 200m world title was deadly serious. Not only did he secure his 10th world championship gold medal but the manner of victory – his time of 19.55sec was the 10th fastest ever and his best for three years – was a stunning riposte to any doubters.

Having struggled with injury all season, afterwards the Jamaican was bubbling enthusiastically about breaking 19 seconds over his favourite distance.

Even Bolt’s victory lap came with added drama when a cameraman on a motorised two-wheel contraption knocked him over from behind then a volunteer attempted to make off with his spikes. “I am fine. I have a few cuts. But it’s nothing I have never done to myself in training. I feel like Justin Gatlin had something to do with it. Maybe,” he said with a laugh.

Facebook Twitter Pinterest Watch as Usain Bolt is floored by a cameraman on a Segway.

Before their 100m clash on Sunday, Bolt had appeared uncharacteristically nervous and had to come to terms with the unfamiliar feeling of being second favourite behind the man with the fastest times in the world this year. But it was as though victory for Bolt then, and the brouhaha that surrounded it, had diminished the American and only enhanced the Jamaican’s power to intimidate. His old swagger was restored and by the time he crossed the line after accelerating away from Gatlin as they rounded the back of the curve, it had become a gleeful strut and he thumped his chest in celebration.

“The 200m means a lot more to me. There was never a doubt that I was going to win this one,” Bolt said. “Justin Gatlin was there: ‘Oh, he is going to be ready’. That is why I really celebrated as much as I did. I am No1.”

After the 100m Gatlin, twice banned for doping violations and running faster than ever at 33, refused to take any questions on his past and subsequently said he would not speak to the BBC over its styling of the race as a battle for the soul of the sport.

Bolt admitted after doing the double for the second world championships running that he had not appreciated the magnitude of interest in their rivalry until after the race. “I really don’t think I did until all of the media flooded the airwaves and social media, I saw people talking. Then I noticed that was really a big deal.”

As the cameras panned the start line, a relaxed looking Bolt kissed the Jamaica badge on his vest and held his fingers in a V for victory sign. It was to prove prophetic.

World Athletics Championships: Usain Bolt beats Justin Gatlin in 200m final – as it happened Read more

If Sunday’s victory in the 100m was unexpected, Bolt shrugging off rusty form and a stumbling semi-final to overcome his relentless rival, in the 200m he soared back to his supremely confident best.

Gatlin, who like Bolt started strongly but was unable to cope when the Jamaican eased away down the back straight, finished second in 19.74. By the last 50m, Bolt was coasting.

Behind the main protagonists, the South African Anaso Jobodwana took bronze in a national record time of 19.87.

Amid the usual colour, carnival and chaos afterwards – the Jamaicans in the crowd chanting “U-sain Bolt!” and well-to-do Chinese children in yellow and black reminding the world that he is a brand apart in a sport he at times carries on his shoulders – there was an edge to his celebrations. “Why I really celebrated was Justin Gatlin said earlier in the week that he was going to bring out something special for the 200m,” Bolt said. “I was like: ‘Yo, you don’t talk about my 200m like that’. I had to prove to him that I am No1.” He did. And how.

The caravan of comment and controversy around this rivalry, which has both gripped the public and raised a host of awkward questions for the sport, will now move to the 4x100m relay on Saturday.

Usain Bolt wiped out by cameraman on segway when celebrating 200m gold Read more

As for Gatlin, he has given up trying to explain or justify his past. “It was never my intention to win over any fans and change the view of who I am,” he said. “My job was to compete to the best of my abilities. I have no ill will towards Usain, no ill will towards anybody.”

Zharnel Hughes, the Anguilla-born British athlete who trains with Bolt’s group in Jamaica, crossed the line fifth in a personal best of 20.02. “It’s my first world championships, I have many more to come,” said the 20-year-old. “This one is just like, in school sometimes you fail your exams. You study again and come back.”

After the race Bolt again paid tribute to his coach, Glen Mills, and his German doctor, Hans-Wilhelm Müller-Wohlfahrt, for getting him into championship shape. He then teased that he may yet retire after the Rio Olympics at the age of 30.

That is a suggestion that will have the organisers of the London 2017 world championships reaching for their prayer books. “I really want, I really want to run at London,” he said. “But I think the sport is not as fun as it used to be. It’s more taxing. I can’t enjoy it as much as I want to because I have to be sacrificing a lot more. So, it’s 50-50, I am telling you.” Whenever he goes, he will leave a huge void in his wake.