Noah Lyles takes semi-final one - just!

He wins with a time of 9.92, just ahead of Kayinsola Ajayi of Nigeria with 9.93 and South Africa's Akani Simbine in 9.96.

Great Britain's Jeremiah Azu takes fourth with 10.05 and for now is in the second of two non-automatic qualifying positions, with two more semi-finals to run.

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Everyone's in the blocks.

Time for the men's 100m semi-finals.

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Noah Lyles won three gold medals at the 2023 World Championships in Budapest, before claiming the Olympic 100m title at Paris 2024.

However, he is not the favourite for gold in Tokyo as he targets a third consecutive world title.

Lyles had an injury-disrupted start to this season and his 100m season's best of 9.90 seconds ranks 14th fastest in 2025.

He was comprehensively beaten by Jamaica's Oblique Seville over the distance in August, while Kishane Thompson holds the title of the fastest man in the world this year (9.75).

But after qualifying for the semi-finals as the fourth fastest overall, Lyles is confident he can defend his title.

"I had a great start today but I had even better ones at practice. I know there is more in the tank," said Lyles.

"This is the best form I have ever been in my life. I am bringing special things here. Running 9.95 in the first round is exactly what I wanted to warm up my body."

Colin Jackson
Two-time world 110m hurdles champion on BBC TV

Each of these semi-finals are the equivalent of any good Diamond League meeting, so there's tension to get through to the final.

Julien Alfred looked all of an Olympic champion there. It's her era now.

Jeremiah Azu, Zharnel Hughes and Romell Glave are the British trio looking to reach the men's 100m final.

Azu and Hughes progressed through Saturday's heats with little fuss, but Glave had to wait to find out if he would be one of the quickest non-automatic qualifiers after he finished his heat in fourth.

Glave equalled his personal best of 10 seconds, and was quicker on the day than both of his compatriots.

Azu lines up alongside Olympic champion Noah Lyles in heat one, as well as 2020 Olympic champion Lamont Marcell Jacobs.

Hughes goes head-to-head with Lyles' arch-rival Kishane Thompson, who is favourite to take gold in Tokyo.

In heat three, Glave must deal with Olympic 200m champion Letsile Tebogo and Oblique Seville, the second fastest man in history to never win a major individual medal.

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Since Usain Bolt retired in 2017, Jamaica's grip on sprinting has loosened.

No Jamaican man has won a global 100m title since Bolt won gold at Rio 2016.

Kishane Thompson, Oblique Seville and Ackeem Blake are looking to end the dry spell.

Thompson missed out on Olympic gold last summer by five-thousandths of a second, but he is the fastest man in the world this year (9.75 seconds).

Seville is the second fastest man in history to never win a major individual medal, but arrived in Tokyo in good form after a commanding win over Olympic champion Noah Lyles at the Lausanne Diamond League.

Defending champion Melissa Jefferson-Wooden takes heat three in 10.73 seconds, with Jamaica's Tina Clayton second.

Dina Asher-Smith comes third in 11.02, which is enough to steal British team-mate Amy Hunt's place as one of the two quickest non-automatic qualifiers.

Asher-Smith will mark her seventh World Championships with a 100m final, with Daryll Neita and Hunt missing out.

Harry Poole
BBC Sport in Tokyo

Daryll Neita leaves the hot seat reserved for the current two fastest non-automatic finishers, to be replaced by British team-mate Amy Hunt. Sport can be cruel.

That is gutting for Neita, having looked so good in the heats and been so determined here to claim her first global medal after going agonisingly close at Paris 2024.

Now it is Hunt sat just down below the media seats here with her fingers crossed, hoping she can hang on to a place in the final.

As for Shelly-Ann Fraser-Pryce, well, the fact her name has been cheered as loudly as that of any Japanese athlete over the past two days tells its own story.

And she might just be writing one last remarkable chapter here.

Semi-final two goes to the Olympic champion!

Julien Alfred of Saint Lucia takes it with a time of 10.93, placing ahead of Jamaica's Shelly-Ann Fraser-Pryce, the 38-year-old running in her final championships.

Great Britain's Amy Hunt takes third with 11.05, that's one hundredth of a second faster than compatriot Daryll Neita and she knocks her team-mate out of the fastest non-automatic qualifying positions.

The two athletes in those spots get track-side chairs and Neita vacates one as Hunt's result comes through, bidding farewell to Sha'Carri Richardson who still holds the other chair.

Harry Poole
BBC Sport in Tokyo

The big group of Jamaican fans who had booked out the seats directly on the finish line yesterday are back again this evening, proudly wearing the yellow and green colours of their national flag.

They've also come equipped with Shelly-Ann Fraser-Pryce face masks in preparation to support the Jamaican great as she contests the final 100m competition of her career.

They will desperately hope that the 38-year-old has the opportunity to race twice this evening as she looks to sign off in style with an individual podium.

And they could have more than one medal to celebrate, with Kishane Thompson and Oblique Seville among the contenders in the men's competition.

Image source, Bbc

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Drama to start the 100m semi-finals, as defending world champion Sha''Carri Richardson twitches her head and causes a false start.

The American is spared disqualification and is shown a green card,

36-year-old Marie-Josee Ta Lou-Smith wins in 10.94 seconds, with 2023 silver medalist Shericka Jackson second with 10.97.

Richardson comes third with a season best of 11.00, and Great Britain's Daryll Neita comes fourth with 11.06.

She'll have to wait and see if she is one of the two-fastest non-automatic qualifiers.

Harry Poole
BBC Sport in Tokyo

We got a taste of what's to come this evening in yesterday's 100m heats, and even that was enough to get the crowd very, very excited.

Prepare yourselves, because over the next two hours we're going to have eight 100m races and crown two world 100m champions.

Noah Lyles claimed he is in the form of his life as he looks to win a third consecutive global 100m title. The question is whether that will be enough, with Jamaican's Kishane Thompson and Oblique Seville among those hoping to dethrone him.

Meanwhile, is the women's event a two-horse race between American Melissa Jefferson-Wooden and Julien Alfred?

Opinions could very well change over the course of these semi-finals.

Image source, Getty Images

There are three Brits to keep an eye on in the women's 100m semi-finals, as Daryll Neita, Amy Hunt and Dina Asher-Smith look to qualify for the final in less than two hours' time.

Neita is up against defending world champion Sha''Carri Richardson in heat one - who received a wildcard to compete after failing to break 11 seconds this season - and Marie-Josee Ta Lou-Smith.

In heat two, Hunt finds herself in a strong field containing Olympic champion Julien Alfred, Twanisha Terry and Shelly-Ann Fraser-Pryce, who is looking to win a medal in her final event before retirement.

Asher-Smith comes up against the formidable Melissa Jefferson-Wooden in the final heat, who is unbeaten this year and practically jogged over the finish line in her Saturday heat.

Tina Clayton will be a force to be reckoned with as well - the Jamaican is the third quickest female sprinter on the planet this year.

Great Britain's Yemi Mary John has been speaking to BBC Sport after her women's 400m heat: "The energy was incredible. I always love racing in championships like this, but this is my first individual so I'm just soaking it in and enjoying every moment of it. Hopefully I make it through to the semi-finals, I do think I ran hard in my heat so hopefully I'm through.

"In the outside lanes, you can't see anyone so you can't really assess where you are until almost the last 150 metres. It can definitely be harder being in one of the outside lanes, but it was just about focusing on my lane, focusing on my race and hopefully booking my ticket to the next round.

"I know how to run championships, but this is a whole new level. We've already seen some incredibly fast women and there's so much competition here, so I'm buzzing."

Colin Jackson
Two-time world 110m hurdles champion on BBC Two

It's really good that we've still got Yemi Mary John and Christine Ohuruogu in that 'next best' section, just!

We're seeing athletes that we don't always see in the Diamond League coming here and racing well. Most of them look nicely prepared for these World Championships. They will not be intimidated and will commit themselves early on to these good performances and national records.

Marileidy Paulino is one of the favourites for me.

Great Britain's Amber Anning makes a strong run to finish second in heat six in 49.96 seconds.

Defending champion Marileidy Paulino of the Dominican Republic wins it in 49.85, with Egypt's Bassant Hemida through in third with a new national record of 50.36.

That final heat confirms that Britain's Yemi Mary John and Victoria Ohuruogu progress to Tuesday's semi-finals among the six quickest non-automatic qualifiers. Phew!

Harry Poole
BBC Sport in Tokyo

I don't want to keep banging on about the heat, but WOW.

After a few hours in the air conditioned comfort of the media centre, walking out into the stadium felt like opening the door of a sauna.

That is only a very slight exaggeration.

There's no breeze whatsoever. Decent conditions for fast times, less so for the men's 10,000m runners who will be out here a bit later on. They'll hope the temperature nudges down slightly before then.

Salwa Eid Naser of Bahrain, the silver medallist in Paris last year, wins heat five in 49.13.

Stacey Ann Williams of Jamaica takes second with a personal best of 49.59, having set off quickly.

Great Britain's Victoria Ohuruogu is in fourth, and her time of 51.37 puts her in the fifth of six non-automatic qualifier positions, with one heat to come.

Colin Jackson
Two-time world 110m hurdles champion on BBC Two

A good run from Great Britain's Yemi Mary John and Jamaica's Nickisha Pryce. The Jamaican is one of the rare women that have gone under the 49-second mark as well.

There was no messing about. Pryce ran a committed first 100 metres, she had nice control and managed to balance her form all the way round.

Balance is so important because you have to go out committed, use the first bit of the energy system well, put your stride in, look out for the danger zone around the bend and make sure not to tax yourself too much for the backend of the race.