Argh and now a false start from Nigeria's Favour Ashe.

Off he slumps.

Kerley still looks cool behind his yellow shades.

Kerley and the other runners in this 100m heats are asked to stand up from their blocks for a second time.

Not ideal.

Defending champion Fred Kerley is up in the next 100m heat.

They're being made to wait a long while on the start line.

Never good for the nerves, I'm told.

Harry Poole
BBC Sport in Budapest

Welcome to the 'q room', where you have everything you need... until you're kicked out.

In a tweak to the rules, qualification can now only be achieved automatically in all events from 1500m up to 5,000m.

Meanwhile, for the athletes who do not secure an automatic qualification place in the sprints, hurdles and 800m, they will wait to learn their fate in the track-side ‘q room’.

There, they are able to sit back, relax, refuel and recover while watching the action on a TV as their rivals attempt to bump them out.

Luxury, for a little while at least.

Reece Prescod has a nervy look up to the big screen after his 100m heat but he, like fellow Britons Zharnel Hughes and Eugene Amo-Dadzie, has done enough to qualify from his heat.

Kwamz: Zharnel Hughes is quiiiick!

Here's how Zharnel Hughes made it through in his 100m heat...

Hello Eugene Amo-Dadzie!

The Briton, dubbed the world's fastest accountant by Steve Cram, makes a flying start to his 100m and goes on to qualify - only losing out on the win in a photo finish.

The US champion Cravont Charleston is left for dust.

31-year-old Amo-Dadzie is on his debut at this level and is on a break from work to be here.

Harry Poole
BBC Sport in Budapest

Katarina Johnson-Thompson would have expected to concede ground in the shot put, but even so she doesn't appear thrilled with her efforts her as she spins away and turns her attention to the 200m, which is less than an hour away.

That fourth event should tell us much more about her medal chances here.

For now, the Americans, led by 22-year-old phenomenon Anna Hall, are in charge and on for a clean sweep...

Here's confirmation of the heptathlon standings following the conclusion of the shot put. Katarina Johnson-Thompson is still in touch of the medal places.

1. Hall (US) 2975
2. Hawkins (US) 2955
3. Brooks (US) 2893
4. Weissenberg (Ger) 2885
5. Johnson-Thompson (GB) 2874

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

This is going to be a very exciting 100m. If you ran this race five or six times then I think you'd get a different winner every time. That's how competitive this race is.

Woooft!

That's why Noah Lyles was confident.

He gets a good start and only gets better to win in 9.95 seconds, pipping Commonwealth champion Ferdinand Omanyala on the line.

Both men make it through.

American Noah Lyles, ever the showman, is hyping up the crowd on the start line.

Can he make it through in this second 100m heat?

Harry Poole
BBC Sport in Budapest

Zharnel Hughes was giving nothing away after crossing the line.

Once he got up in to his stride he was able to power to the front, allowing himself the time to take a cool look to his right and check victory was assured.

Similarly to Usain Bolt, his tall frame means he is a relatively slow starter - but he'll be keen to sharpen up out of the blocks in tomorrow's semi-finals.

Most importantly, that's job done for now.

Image source, Getty Images

• 18:43: Men’s 100m heats - Zharnel Hughes, Fred Kerley, Noah Lyles, Marcel Jacobs
• 19:31: Heptathlon 200m
• 19:37: Men's shot put final
• 19:55: Women’s 10,000m final - stacked field including world record holder Letesenbet Gidey and Sifan Hassan
• 20:49: 4x400m mixed final - GB second fastest in heats

Steve Cram
Marathon commentator on BBC TV

This is the moment for Zharnel Hughes, he's in the shape of his life. 39 men have run under 10 seconds this year. Since 2015 it's been a journey that has a taken a little longer than some would have thought to get to this position.

That's impressive from Great Britain's Zharnel Hughes, who makes a ropey start before powering through the field to take the win in 9.99 seconds.

Job done.

Zharnel Hughes looks calm as you like as he gives a wave on the start line.

The first two in each heat go through automatically.

On your marks...

Harry Poole
BBC Sport in Budapest

Image source, Getty Images

Athletics' blue riband event rarely disappoints.

But the 100m at these World Championships - and the sprints more widely - promise to provide terrific entertainment, with wide-open competition and a range of personalities colliding in Budapest.

Zharnel Hughes has his work cut out to win his first global medal this weekend, facing competition from the Olympic 100m champion and both the world 100m and 200m champions to list but a few contenders.

However, the Briton, who predicted both of his British record runs this season, is in the form of his life.

During my interview with him earlier this year, the start list for the London Diamond League 200m was announced and his face lit up at the prospect of facing the likes of Noah Lyles in front of 50,000 fans.

Full of confidence and with the results to back it up, the fastest man in the world this year will not be fazed by the challenge ahead one bit.