Former Boise State track and field captain Nick Cunningham struggled Sunday and is the third-ranked American pilot at the halfway point of the four-run competition, which concludes with two runs Monday.
"Not how I thought tonight would go, but that's racing. Coming out tomorrow to try and save some face,'' Cunningham said on Twitter.
Russia's Alexander Zubkov emerged as the clear leader, setting a track record on his first run. He has a commanding lead over Switzerland's Beat Hefti and American Steven Holcomb, the defending Olympic champion in four-man. Zubkov is two runs away from winning Russia's first gold medal in two-man since 1988.