South Africa's Van Niekerk wins 400m in 43.48 seconds
Gatlin (19.87) & Bolt (19.96) win their 200m semis
GB's Zharnel Hughes wins his semi in 20.14
Eilidh Child sixth in 400m hurdles final
Dina Asher-Smith fastest qualifier in 200m heats
LaShawn Merritt explodes out of the blocks like a firecracker. Can anyone chase him down? Yep. South Africa's Wayde van Niekerk gets him at the bend and is home and dry in 43.48.
That puts the South African fourth in the all-time list. Merritt takes silver in a personal best 43.65, while Olympic champion Kirani James ends up with a bronze in a season's best 43.78.
Michael Johnson
400m world record holder on BBC TV
Quote MessageThis is the highest quality field of 400m runners I have seen in a long time. Six of the eight athletes in the field have under 44 seconds, we haven't see that in the 400m for quite some time.
Olympic champ Kirani James was beaten by LaShawn Merrit in the 2013 World Championships final, of course, and the American is in contention again, in Beijing to defend his title.
Britain's Rabah Yousif Bkheit, who set a personal best in the semi-final, crosses his fingers as he's announced.
"I'm going to declare war now. I'm going to chase after a medal," he said after progressing to the final.
Image source, Getty ImagesThat hour is now upon us. The curtain will close on day five of the World Championships when the 400m final concludes.
The one-lap kings set quick times in the heats, not so quick in the semi-finals, so how fast will they go today?
It's very much seen as a battle between Olympic champion Kirani James and South Africa's Wayde van Niekerk.
Quote MessageI am a bit tired and need some rest, but I am feeling OK. I tried to preserve some energy for the final. The 200m is my best event and I believe I will do well."
Usain Bolt after winning his 200m semi-final
Image source, Getty ImagesThe draw for Thursday's 200m final has been revealed and Britain's Zharnel Hughes has drawn the short straw. He's in lane five, which doesn't sound so bad, but he's got Justin Gatlin inside him in lane four and training partner Usain Bolt outside him in lane six.
Allison Curbishley
BBC athletics expert on Radio 5 live
Quote MessageThat looked like it was going to be a German victory but what a run from the Kenyan athlete. She didn't take the water jump the prettiest but she wanted the gold the most.
Andrew Cotter
BBC Sport commentator
Quote MessageKenya are collecting gold after gold, what a championship they are having.
Image source, Getty ImagesWhat a finish. There were three in contention... swaying, running like they've been on the hard liquor such punishment their legs have taken.
But it was Kenya's Hyvin Jepkemoi who had the speed to pull clear of the rest, winning in 9:19.11.
Tunisia's Habiba Ghribi had to make do with second, while Germany's Gesa Felicitas Krause was third.
The pole jump final is reaching a conclusion and, on her final attempt, Cuba's Yarisley Silva clears 4.90m! Bravo. Her team are cock-a-hoop and who can blame them. Their lady has one hand on the gold medal.
Image source, Getty ImagesThe next gold medal will be awarded to the best female 3,000m steeplechaser in the world. Kenya's Virginia Nyambura, victorious in three Diamond League races this year, is one of the favourites.
The others to keep an eye on are Tunisia's Habiba Ghribi and Ethiopian duo Hiwot Ayalew and Sofia Assefa.
Holly Bradshaw fails all three attempts at 4.80, which means the Briton has no chance of winning a medal in the pole vault.
She did vault a season's best 4.70m, though, and can say she's the seventh best pole vaulter in the world
Image source, Getty Images
Colin Jackson
Two-time world 110m hurdles champion on BBC TV
Image source, ReutersQuote MessageBolt was just in cruise mode and did enough to come off the bend in first place. He has so much spare. He is maybe looking to do something special in that final.
Darren Campbell
Former British sprinter on BBC Radio 5 live
Quote Message"Gatlin will have to jump all over Bolt around the bend. The lane draw will be so important in the final. Can Gatlin put Bolt under pressure? This is getting more and more exciting.
Usain Bolt closes in on Danny Talbot coming into the bend and it's easy for the six-time Olympic champion, who wins in a season's best 19.96.
Talbot was sixth, producing a personal best 20.27.
The two other automatic qualifiers were South Africa's Anaso Jobodwana (20.01) and Turkey's Ramil Guliyev (20.10).
Image source, Getty ImagesMichael Johnson
400m world record holder on BBC TV
Quote Message19.87 secs is worrying for everyone in the 200m, that is faster than most athletes in the field and Gatlin cruised to it.