|World Athletics Championships on the BBC|
|Venue: London Stadium Dates: 4-13 August|
|Coverage: Live across BBC One and Two, BBC Radio 5 live, BBC Radio 5 live sports extra, the BBC Sport website and app. Click for times|
Ciara Mageean failed to make it out of the 1500m heats as she came in last of the 13 finishers in heat one on the opening day of the World Championships.
The Portaferry woman clocked a time of 4:10.60, well short of her lifetime best of 4:01.46 set in Paris last year.
Ethiopian world record holder Genzebe Dibaba won a fast heat in 4:02.67, with South African Olympic 800m champion Caster Semenya second in 4:02.84.
Kenya's Winny Chebet was third, with Great Britain's Jess Judd sixth.
"That race was a disaster. I'm good enough to qualify for the semi-finals and battle for the final but that just wasn't me out there. It's very disappointing," said Mageean after Friday night's event.
"I couldn't get my legs turning over - I don't know, I really don't.
"Everything has been going well this season and I've been going from strength to strength so to not make it out of the rounds is a disaster."
The top six finishers from each of the three heats will contest the semi-finals in London on Saturday, along with the next six fastest runners from all the heats.
Dibaba's performance will give her confidence that she can retain her World Championship crown.
Mageean, 25, earned a bronze medal at the European outdoor championships last year, and had a best time this season of 4:03.57 set in the mile race at the Diamond League meeting in London.