Usain Bolt remains on course for another gold medal hat-trick after avoiding a World Championship-ending injury at the hands of a runaway segway.
Fresh from riding to the rescue of his beleaguered sport in the 100 metres, the Jamaican attempted to make it four successive half-lap world crowns in Beijing.
Two-time drugs cheat Justin Gatlin again stood in his way but once more failed to wrestle away gold as Bolt held strong down the home straight to win with a world-leading 19.55 seconds.
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The 29-year-old finished the 200m final an impressive 0.19 secs ahead of Gatlin, whose comments in the build-up clearly irked the Jamaican sprint great.
"It was never a doubt to me," Bolt said after the standard exuberant celebrations. "Maybe I doubt a lot of people, but I never doubt that I will win my 200 metres.
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"I wasn't worried. I knew I had to run the first 150 hard. After the first 150, I looked across and I could see that Justin Gatlin was tiring and then it was never a doubt I would win the race.
"Why I really celebrated was because Justin Gatlin said earlier in the week that he was going to bring out something special for the 200 metres.
"I was like 'yo, you don't talk about my 200 metres like that', so I had to prove to him that I am number one."
Those celebrations were, as always, lapped up by the crowd, with some of the "crazy fans" trying to get closer to the 200m champion by jumping the barrier.
They were swiftly ushered away by the stadium's heavy-handed security team, although they could not protect Bolt from an unusual threat.
A TV cameraman was trailing Bolt's celebrations when the wheel of his segway rolled up on to a camera track, changing the vehicle's direction and taking the sprinter out from behind.
There was an audible gasp inside the Bird's Nest as the double gold medallist was wiped out, but he quickly composed himself and allayed fears of any lasting impact afterwards.
"It didn't actually hit me in my Achilles, it hit me in my calf area," Bolt confirmed to Press Association Sport. "It's alright, I will get over it.
"Never a doubt (for the relays), never a doubt. I am just going to get it massaged, ice it up a bit and I should be fine."
The 4x100m relays get under way on Saturday with the heats - a session Great Britain's Dina Asher-Smith may well be rested for after what looks set to be a memorable day.
The 19-year-old history student came within two hundredths of a second of Kathy Cook's 31-year-old British record as she won her 200m semi-final convincingly in 22.12 seconds at the Bird's Nest.
Asher-Smith has set two personal bests in as many days and looks a strong contender to become the first British woman in a generation to win a global 100 or 200m medal.
"I was happy to stay composed," she said. "I'm not letting it sink in.
"It's great doing well in the heats and the semis, but the final is where it counts. I'm happy, but I can't let myself get caught up in the moment."
Elsewhere tonight, Katarina Johnson-Thompson, Shara Proctor and Lorraine Ugen will attempt to secure a podium place in the long jump.
In the morning session, Olympic bronze medallist Robbie Grabarz failed to make the high jump final.
The 27-year-old was the only British athlete in action, clearing 2.22 and 2.26m at the first time of asking.
However, Grabarz failed three times to make 2.29m, leaving him outside the top 12 and ending his hopes of a place in the final.
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