ISTANBUL (AP) -- Jessica Ennis of Britain closed in on a second straight pentathlon world indoor title Friday, with Russian rival Tatyana Chernova fading outside the medal positions.
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.
Ennis bolted out of the blocks of the 60 meters hurdles and left the Russian with an unbridgeable gap. She crossed in 7.91 seconds and led the outdoor heptathlon champion by a 0.38 seconds.
The defending champion Ennis extended her lead by clearing 1.87 meters in the high jump, compared to Chernova's 1.84. Ennis set a personal best of 14.79 meters in the shot put as Chernova fell further back.
"The shot put's been going well and it's great to come out here and be competitive," Ennis said.
With two events to go, Ennis leads with 3,064 points, while Chernova was way back in fifth place with 2,880.
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.
While Defar can rest until Sunday, Ennis and Chernova had three more events to go before Friday's finale.
Beyond the title on Friday, the clash is also about bragging rights going into the London Olympics. Chernova beat Ennis in the seven-event heptathlon at the world championships last year in Daegu, South Korea, and Ennis wants some gold of her own going into her home games.
It made it all the more important to get off to a "great start" for Ennis, who ran her second-fastest time in the race.
Associated Press writer Chris Torchia contributed to this report.