HELSINKI -- Evgenia Medvedeva closed in on a second world figure skating title Wednesday by taking the lead in the short program, while China's Sui Wenjing and Han Cong led the pairs.
Russia's Medvedeva, 17, skated flawlessly and scored 79.01 points, a result second only to the world-record score she posted at December's Grand Prix finals.
Medvedeva, who is unbeaten since November 2015, can become the first woman to win back-to-back world titles since 2001 if she holds on to her lead in Friday's free skate.
"I'll try to show everything I can do in the free skate," Medvedeva said.
Two Canadians trailed Medvedeva: Kaetlyn Osmond is second with 75.98 points and Gabrielle Daleman third with 72.19.
Osmond, in her first world championships since 2014, put her success down to a more focused approach.
"I was just loving every minute of it and completely in the moment," Osmond said. "I know how to deal a little bit more with the excitement, and hopefully I can just stay that way for the long [program]."
Osmond will skate last Friday, a position which can put some skaters under pressure. But the Canadian said it "has always been my favorite spot to compete."
Daleman is following up on her first major championship medal. She won silver at the Four Continents Championship.
"I almost never really truly believed in myself that much, and then over the last two seasons it just kept coming together," Daleman said.
Last year's bronze medalist, Anna Pogorilaya, had to settle for 71.52 points and fourth place. U.S. national champion Karen Chen led the American team in fifth, with veteran Ashley Wagner seventh and Mariah Bell 13th.
Six-time world championship medalist Carolina Kostner of Italy struggled in eighth after making a crucial error on a flying camel spin.
Competing at her first world championship since a ban for lying to anti-doping officials, Kostner admitted it was hard to recover her previous form.
"I'm very aware that I cannot just stay out and then think that everything will fall into your lap," she said.
In the pairs short program, Sui and Han skated cleanly to score 81.23 and beat Germans Aliona Savchenko and Bruno Massot into second place on 79.84. However, reigning world champions Meagan Duhamel and Eric Radford were the surprise of the night, reacting in shock as the judges placed them seventh after a sometimes erratic performance.
Russians Evgenia Tarasova and Vladimir Morozov skated to an impressive third place on 79.37 after a training accident cast doubt over whether they could even compete.
Their coach, Nina Mozer, told Russian media that the blade of Morozov's skate had sliced into Tarasova's knee Wednesday morning, leaving her needing stitches.