|World Athletics Championships on the BBC|
|Venue: London Stadium Dates: 4-13 August|
|Coverage: Live across BBC One and Two, BBC Radio 5 live, BBC Radio 5 live sports extra, the BBC Sport website and app. Click for times|
Wayde van Niekerk stormed to the first part of his potential golden double as he retained his world 400m title with a dominant display.
With one of his main rivals, Isaac Makwala, absent after being excluded controversially on medical grounds, Olympic champion and world record holder Van Niekerk left the rest of the field in his wake, underlining his status as the sport's new superstar in the post-Usain Bolt world.
The South African's time of 43.98 seconds was almost a second down on the astonishing record he set a year ago in Rio, but he was still 0.43secs clear of Steven Gardiner in second and the fast-finishing Abdalelah Haroun in third.
- 'Decision to withdraw Makwala disturbing'
- Day-to-day guide - what to watch and when
- Medal table & GB medallists
On a night when Britain's Kyle Langford continued the series of near-misses for the host nation by finishing an agonising 0.04secs off an 800m bronze, the row over Makwala's exclusion saw a bitter exchange of words between his Botswanan team and the IAAF medical team.
Whether Makwala, who was chasing his own 200m/400m double, would have got close to Van Niekerk is another matter, as the favourite was able to ease off in the final few metres without ever looking as if he had extended himself.
In front of another capacity crowd at the London Stadium, a brilliant pole vault competition won by USA's Sam Kendricks and the 800m victory of France's Pierre-Ambroise Bosse also helped light up a cold night.
Van Niekerk on track
With Usain Bolt having run his last individual championship race, much weight has been placed on Van Niekerk's lean shoulders as his sport desperately seeks fresh stars to fill the void left by arguably the greatest athlete of all time.
Van Niekerk does not have the same natural showman's character as the Jamaican, but with the 200m lacking a dominant figure now Bolt has gone, he has a wonderful chance of becoming the first man since Michael Johnson to win the double at a World Championships.
His recovery time is limited - the 200m semi-finals are on Wednesday night, the final on Thursday - and if he makes it through, he will have run six races in six days.
But he has the speed and he has the form, with Makwala left in limbo after his Botswanan team failed to overturn an IAAF ruling that he should be banned from the track after reportedly suffering from the same norovirus that has hit several athletes at these championships.
Van Niekerk had sympathy for Makwala, saying: "It was definitely a heartbreaking moment. I saw him just before the 200m heat and the only thing I could think of was just wrapping my arms around him and telling him he should get well soon.
"I wish I could give him my medal to be honest, but this is sport."
Bosse on top as Kendricks keeps record intact
Langford, 21, timed his 800m effort close to perfection in his first major senior final, knocking 0.2secs off his previous best as he came from last to within a fraction of the podium.
In a contest left wide open in the absence of several big names led by double Olympic champion David Rudisha, Bosse took control with 200m to go to take gold in a season's best of one minute 44.67 seconds. Poland's Adam Kszczot won silver and Kenya's Kipyegon Bett just clung on to bronze.
"I was so close to getting a medal and so close to getting a silver and a gold. I wasn't far at all, half-a-second, if that," said Langford.
"It's a gutting thing being so close and closing on these guys.
"But as I get stronger and older - I'm only 21. I'm pretty sure I'll be in the mix with these guys.
"It was a scrappy race. Perhaps I left it too late but I won't be making the same mistake come Tokyo, I can promise you I'll be getting that gold."
Kendricks, who serves in the US Army reserve, is unbeaten outdoors this summer and came through a ding-dong battle to hold off Poland's Piotr Lisek and France's world record holder Renaud Lavillenie, clearing 5.95m at the third attempt.
Twice world silver medallist Conseslus Kipruto went one better as he held off Soufiane Elbakkali to win 3,000m steeplechase gold and maintain Kenya's stranglehold on the event.
It is 30 years since anyone from outside his nation has won a Olympic or world title in the event, and although the USA's Evan Jager led until there were 200m to go, he had to settle for bronze a year after taking silver in Rio.
Earlier, the Czech Republic's Barbora Spotakova won back her javelin world title at the age of 36, with her second round effort of 66.76m denying Li Lingwei, despite the Chinese thrower conjuring up a personal best of 66.25.
British team captain Eilidh Doyle is into the 400m hurdles final after taking one of the two fastest qualifiers slots from the semi-finals. It is the fourth consecutive global final the 30-year-old has reached.
Dina Asher-Smith made it out of the 200m heats, impressing after a season that appeared wrecked when she broke her foot in a gym accident, and was joined in the semi-finals by compatriot Bianca Williams.