Ireland’s Siofra Cleirigh-Buttner finished sixth in the 800m heats at the World Championships in London.

Competing in her first global major championships, Cleirigh-Buttner sat at the back of the field of seven athletes for the first lap.

As the pack approached the second and final lap, Cleirigh-Buttner moved into sixth, overtaking Jamaican Kimarra McDonald. With 200m to go, the five athletes ahead of Cleirigh-Buttner increased the pace, but unfortunately the 22-year-old couldn’t kick on to close the gap, clocking 2:06.54 as she crossed the line in sixth place, over four seconds off her season’s best of 2:02.11.

The heat (heat five) was won by American Charlene Lipsey in 2:02.74, with Norway’s Hedda Hynne finishing second in 2:02.85. Docus Ajok of Uganda finished 3rd to seal the final automatic qualifying spot.

Cleirigh-Buttner was a late addition to the Irish team for the World Championships, gaining a place via the IAAF roll-down process.

The young Irish athlete has a 800m personal best of 2:01.98.

Speaking to Athletics Ireland after her heat Cleirigh-Buttner said: “I came here to compete with an outside chance of getting through. I think I did myself proud.”

Earlier this year at the European U23 championships, Cleirigh-Buttner finished 7th in the 800m final in 2:06.40.

South Africa’s Olympic champion Caster Semenya eased through to the 800m semi-finals with 2:01.33 in heat three, while defending world champion Marina Arzamasova of Belarus failed to advance.

Britain’s Lyndsey Sharp ran a strong 800m in heat four, crossing the line in 2:01.04 for second place, finishing behind Kenya’s Margaret Wambui with 2:00.75.

Fellow GB athletes Shelayna Oskan-Clarke and Adelle Tracey also qualified for the semi-finals, Oskan-Clarke with a time of 2:01.30 and Tracey with 2:00.28 in their respective heats.