Daisuke Takahashi of Japan performs during the men's free skating competition at the ISU World Figure Skating Championships in Moscow April 28, 2011. [Photo/Agencies]

While Chan and Kozuka excelled, many of the favourites including defending champion Daisuke Takahashi of Japan, flopped.

Takahashi, who in Turin last year became the first Asian male to win the title, was fifth after an error-ridden routine.

Fellow Japanese Nobunari Oda, second at the start of the day, also slumped to sixth.

Kozuka's silver was his best result in a major competition and he was motivated to give Japan something to cheer after last month's devastating earthquake and tsunami forced the championships to be moved from Tokyo to Moscow.

"All I wanted to do is skate my best and I'm glad I was able to bring some good news back home," said the 22-year-old whose previous best result at the world championships was sixth in 2009.

With former world and Olympic gold medallist Yevgeny Plushenko serving an indefinite ban, the home crowd's hopes were pinned on Gachinski and the 17-year-old was equal to the task.

"Of course I was quite nervous before the competition," said the Muscovite who is coached by Plushenko's mentor Alexei Mishin. "But as soon as I came on to the ice the nerves were gone and I was able to show my skills to the fullest."

China's Pang Qing and Tong Jian of China look poised to retain their crown when the pairs event resumes later on Thursday.