That's the fifth-fastest 100m of the season, and Christian Coleman shut off at maybe 75m.

Wow that was rapid!

Adam Gemili is third in 10.13. Close.

1. Coleman
2. Brown
3. Gemili

Christian Coleman jogs 9.88!

Here we go...

Adam Gemili's PB is 9.97. He hasn't gone under 10 this season. He'll need to I reckon to qualify for the final later tonight.

The top two go through.

Coleman prowls up and down in his lane. He jogged 9.98 in the heats. We could see a swift time here.

Image source, BBC Sport

Christian Coleman has the fastest time in the year this time - 9.81.

There's nobody in the stadium, by the way.

World leader Christian Coleman (lane 5) is the clear favourite in the first 100m semi-final but what an opportunity it presents for Adam Gemili (lane 8) to reach his first senior global 100m final. A top-two spot will be tough but, Coleman aside, the rest of the field are within Gemili’s range.

We can see Chris McAlister's mum simply say "well done mate" as her son stands with an ear piece in listening to what his parents have to say to BBC Sport.

In replying, the Great Britain athlete says: "It's amazing to have some support out here. I feel really good. I think I have missed out by a few spots but couldn't have done any more to be honest. I have run my legs ragged."

McAlister ran 49.18 to finish fifth in his heat and asked if the experience will help him in his plans for Tokyo 2020, he replies: "I feel like I am at home here. I've had two races, a holding camp, the team is amazing. It's really good to come out with a PB."

Really strong run from Rai Benjamin - he leads home to win in 48.53, with Abderrahman Samba in second behind him.

All three big guns are safely through.

It’s a clash of the titans with American Rai Benjamin (lane 6) up against home favourite Abderrahman Samba (lane 5).

Some news from the first semi as well - Kyron McMaster has been disqualified. He will appeal that I'm sure.

Sprinter Christian Coleman cannot be the face of athletics following the controversy over his missed drugs tests, says US legend Michael Johnson.

The US Anti-Doping Agency charged Coleman with missing three tests in 12 months before withdrawing the claim.

The 23-year-old American is the fastest man in the world over 100m this year.

"It completely disqualifies him, at this point, from ever being that face of the sport. This will follow him, as it should," Johnson told BBC Sport.

In the first global major outdoor championship since Usain Bolt's retirement, who will step out of the Jamaican's shadow? In truth, the succession happened two years ago in London when Justin Gatlin spoiled Bolt's farewell party to win 2017 World Championships gold. Gatlin, who has served two doping bans and is now 37, is very much still in the medal conversation but the smart money is on American team-mate Christian Coleman.

Saj Chowdhury
BBC Sport in Doha

Those with a penchant for obscure camera angles might have noticed a new one at these championships when Adam Gemili's chin and thighs were treated to an extreme close up.

This is because there are now cameras in the starting blocks!!

We'll be treated to an unflattering view later when the men's 100m semi-finals get under way.

Image source, BBC Sport

Impressive stuff from Elliot Giles.

Karsten Warholm and TJ Holmes take it out, the Norwegian is streets ahead into the home straight though. He can joh the last 50 to win in 48.29.

Abdelmalik Lahoulou comes through to take the second spot. Well judged.

Chris McAlister is down in fifth, he won't qualify but that's a PB of 49.18.

And we're off! Top two go through by right remember.

Michael Johnson
Four-time Olympic gold medallist athlete on BBC TV

Warholm wants to win and also break the world record in Doha. You want to win and don't want to sacrifice the win by going for the record. So he will be biding his time.

Karsten Warholm has his eyes on the world record of 46.78 - that has stood since 1992!