Russia's Alexander Tretiakov clinched the lead in the Olympic men's skeleton after the first day of the competition at the Sanki Sliding Centre.
The 2013 world champion clocked a combined time of 1min 51.99sec after two runs to gain a lead of 0.56sec over two-time world champion Martins Dukurs of Latvia.
In his first run Tretiakov set a new track record of 55.95sec.
John Daly of the United States is in third spot, 1.03sec behind Dukurs.
The medals will be decided after the third and fourth runs on Saturday. The times of all four runs are added together to determine the winner.