Genzebe Dibaba of Ethiopia competes in the women's 5,000-meter heats at the IAAF World Championships in Beijing on Thursday. Photo: CFP

Ethiopia's Genzebe Dibaba eased through to the final of the women's 5,000 meters on Thursday to stay on course for a world athletics championships double, while American Brittney Reese saw her six-year long jump reign end.

The 24-year-old Dibaba, who won the 1,500-meter gold on Tuesday in dominant fashion, was untroubled in the opening heat of the 5,000. She won in a time of 15 minutes 20.82 seconds on another hot and sunny morning at the Bird's Nest ­stadium in Beijing.

Dibaba crossed the line just ahead of Kenyan Mercy Cherono (15:20.94), while compatriot Almaz Ayana, who won bronze two years ago in Moscow, put down a marker for Sunday's final by recording the fastest time of the day, 15:09.40, in the quicker second heat.

"Winning the 1,500-meter gold medal gave me confidence, but you never know what is going to happen in the final," ­Dibaba told reporters

Dibaba showed her skill in the 1,500-meter final by taking the lead with two laps to go and blowing clear with ease. She said a world record was possible in Sunday's 5,000-meter final.

"If I keep my good performance I can run faster than the current world record," she said.

Asbel Kiprop of Kenya also showed his class in the heats for the men's 1,500 ­meters, coasting through to Friday's semifinals in a time of 3:38.97 after winning the second heat.

Elsewhere, on the sixth morning of the championships, triple defending champion and Olympic gold medalist, Reese, missed out on a spot in Friday's long jump final after finishing 24th in the qualifier with a disappointing 6.39 meters.

It was a better day for Briton Katarina Johnson-Thompson at the pit as she booked a spot in the final with an effort of 6.79 meters after three long jump fouls cost her a heptathlon medal on Sunday.

Olympic champion Anna Chicherova of Russia was among a group of experienced high jumpers to secure passage through to Saturday's final.

The 33-year-old cleared the required 1.92-meter mark along with 31-year-old double world champion Blanka Vlasic of Croatia and Spain's 36-year-old European champion Ruth Beitia.