Leading lights sizzle in steamy Osaka

Searing heat, a sizzling track and a stellar start by Sweden's Carolina Kluft dominated day one of the 11th World Championships yesterday.

Tirunesh Dibaba capped the balmy night session with a lion-hearted performance to overcome stomach problems and become the first woman to retain the 10,000 metres crown.

"I almost quit the race but because I was representing my country, I hung in there," the frail 22-year-old panted.

Dibaba's heroics earned Ethiopia a fifth successive world title in the event.

In the championships' blue riband event, Tyson Gay and Asafa Powell roared through two rounds of qualifying to stay on course for their much-anticipated 100m showdown.

Heptathlete Kluft recorded personal bests in the hurdles and high jump and Luke Kibet became the first Kenyan man to win the world marathon title in 20 years.

Gay and world record holder Powell cantered safely through to today's semi-finals.

"I tried to run 10.2 or 10.3 but I couldn't run that slow," Gay quipped after his first heat in 10.19.

His second was quicker, the American finishing in 10.06.

"It's the fastest track I've ever run on," he said, adding weight to his forecast that Powell's world record of 9.77 could fall.

Powell sauntered through his first heat in 10.34 and tore through his second in 10.01.

As the sprinters rocketed, searing heat and sapping humidity produced the slowest men's marathon winner in 11 World Championships.

Kibet took gold in 2 hours 15 minutes 59 seconds. The fastest man in the world this year, Qatar's Hassan Mubarak Shami, held on for silver with Switzerland's Victor Roethlin taking bronze.

"I'm happy and I am proud to win the gold medal for my country," Kibet said. "It's been a long time for Kenya without the gold medal in marathon," he said after emulating compatriot Douglas Wakiihuri's 1987 feat.

The thermometer had tipped 29 degrees Celsius at the 7 a.m. (Japan time) start and had climbed to 33 degrees by the finish.

Kluft on top

Sweden's Kluft enjoyed her morning in the sunshine, taking her customary position at the top of the heptathlon leaderboard.

Following a personal best of 1.95m in the high jump she skipped off the mat and wheeled around the field skipping and circling her arms.

Her 13.15 in the 100m hurdles was also a personal best. She was still smiling when she returned to action in the evening and a throw of 14.81 in the shot put was a season best.

She notched a 2007 best in the 200m, too, and after four events held a 148-point lead over Ukraine's Lyudmyla Blonska.

The 24-year-old Kluft is unbeaten in the seven-sport event since 2002.

"My day was fine, thank you... I am very satisfied with my first day," Kluft smiled.

In the men's shot put, American Reese Hoffa stepped from the shadows to take gold. The 29-year-old fired 22.04 metres to consign 2005 champion and compatriot Adam Nelson to second place.