ISTANBUL (AP) -- Nataliya Dobrynska of Ukraine upstaged favorites Jessica Ennis and Tatyana Chernova on Friday to lead the pentathlon at the world indoor championships going into the closing 800 meters.
In the 400 meters, Sanya Richards-Ross of the United States and Aleksandra Fedoriva won their heats to advance to the final on Saturday at the indoor world championships.
American shot putter Reese Hoffa qualified for the final later Friday. Chaunte Howard Lowe of the United States also went over the qualifying height in the high jump.
Olympic champion Dobrynska had a season's best of 20 feet, 6¾ inches in the long jump and overtook Ennis at the top of the standings. The British defending champion finished with 20-3¾ and fell to third place. World heptathlon champion Chernova jumped 20-6¼ for fourth.
Australian hurdler Sally Pearson set a continental record of 7.85 seconds in the 60-meter hurdles heats. American Kristi Castlin failed to finish when she thought everyone would be pulled back for a false start.
Many racers complained about the starting gun and tough acoustics in the Atakoy Arena.
Ethiopian great Meseret Defar set off on her quest to become the first female athlete to win five world indoor gold medals in a row, easily winning her 3,000 heat.
"My feeling is good and my shape is good," Defar said.
The opening day started well for Ennis of Britain. She bolted out of the blocks of the 60 meters hurdles and crossed in 7.91 seconds, leading the outdoor heptathlon champion Chernova of Russia by a 0.38 seconds.
Beyond the pentathlon title on Friday, the competition is about bragging rights before the London Olympics. Last year, Chernova beat Ennis in the seven-event heptathlon at the world championships in Daegu, South Korea.
Associated Press writer Chris Torchia contributed to this report.