|World Athletics Championships|
|Venue: Beijing National Stadium, China. Dates: 22-30 August.|
|Coverage: Live on BBC TV, Red Button, Radio 5 live, online, mobiles, tablets and app. Click here for full details.|
Great Britain's Christine Ohuruogu failed in her bid to win a third world title as she finished last in the women's 400m behind gold medallist Allyson Felix of the United States.
It was Felix's ninth world title, just one behind Jamaican Usain Bolt's record of 10 gold medals at the Championships.
Felix, 29, dominated from start to finish to win in 49.26 seconds - the best time in the world this year.
Bahamian Shaunae Miller took silver with Jamaican Shericka Jackson third.
Defending champion Ohuruogu, 31, racing on the track she won Olympic gold seven years ago, faded on the home straight and finished in 50.63.
Felix, the Olympic 200-metre champion held a commanding lead by 150m and off the final bend she was clear of her nearest rival Miller, who ran a personal best.
'My title's gone'
Ohuruogu, was hoping to become the first woman to win three 400m world titles after golds in Moscow in 2013 and Osaka in 2007.
But her preparations for Beijing were hampered by a hip injury early in the season.
"I knew Felix was going to go out hard so I knew I had to try and match that and go out hard as well. But she had a kick that I didn't quite know what to do with.
"You've just got to try and make the best of the situation. When the race is fluid you don't really think that much, but I think I was thinking quite a bit, like, 'my title's gone'. And I came last."
BBC athletics commentator Steve Cram: "When Allyson Felix comes past you after 100m what does that do to you psychologically? It must have been soul-destroying for Christine. It was one race too far for her."
Former British sprinter Darren Campbell on BBC Radio 5 live: "Christine kicked early because she tried to close the gap on Allyson Felix which is why she had nothing more to give down the straight. She should have stuck with her race."
Injured Olympic 400m champion Sanya Richards-Ross on Radio 5 live: "That was phenomenal from Allyson Felix. She got out so quickly it put pressure on Christine. It's amazing to see her do this and defend the title for Team USA. I am so glad to call her my team-mate."
Felix's first 400m title
Felix has world and Olympic titles at 200m and in the 4x400m relay, but this was her first major title in the event.
The closest she came was her silver medal at the 2011 World Championships.
"I wanted to challenge myself this year and I did and I'm happy I could be successful. I had to take advantage of the speed that I have and bring that to the 400m."
British record for Hitchon
In the women's hammer final, Sophie Hitchon broke her own British record twice with throws of 73.65m and then 73.86m.
But the 24-year-old former junior world champion was just 16cm off the medal places.
"It's agonisingly close to a medal but coming fourth is really good," Hitchon told the BBC. "I had a rough year last year but two national records and two PBs in one competition, I am super happy with that."
Poland's world record holder Anita Wlodarczyk produced the second longest hammer throw of all time to win the title with a new championship record.
The 30-year-old, who set the world record with a throw of 81.08m earlier this month, secured gold with her fourth effort, a throw of 80.85m.
China's Zhang Wenxiu claimed silver with her best throw of the season (76.33), while France's Alexandra Tavernier took bronze with 74.02
Taylor goes close to triple jump world record
Olympic champion Christian Taylor produced the second longest jump in triple jump history to regain his world title.
On his final effort, the American leapt 18.21m - just eight centimetres short of Jonathan Edwards' world record. The Briton, whose record has stood for 20 years, was watching in the stands.
"That was a remarkable jump," said the BBC Radio 5 live presenter. "Nothing we have seen in the competition had indicated he would jump that far but that was phenomenal."
Cuba's Pedro Pablo Pichardo, Taylor's great rival throughout the season and a man who has also gone over 18m, took silver in 17.73m, while Portugal's Nelson Evora won bronze with a 17.52m leap.
Merritt one step closer to gold
Olympic champion Aries Merritt stormed into the world 110m hurdles final in his penultimate race before undergoing a kidney transplant next week.
The 30-year-old American clocked a season's best 13.08 seconds to win his semi-final in the quickest overall time for Friday's final in Beijing.
Russia's two-time European champion Sergey Shubenkov was second fastest overall in 13.09 with defending champion David Oliver joint sixth in 13.17.