Loch, from Germany, coasted to victory on the 2010 Olympic track and led a 1-2-3-4 sweep by his country on a night when German sleds took five of six medals in two events.
Loch, who is coached by his father and German head coach Norbert Loch, clocked two runs that totalled 1 minute, 36.375 seconds. That was well ahead of Andi Langenhan's 1:36.750, followed by Johannes Ludwig in 1:36.775 for the bronze medal. David Moeller took fourth.
Chris Mazdzer, a 2010 Olympian from Saranac Lake, N.Y., posted his best career result by finishing in sixth place in 1:37.124. Taylor Morris, of South Jordan, Utah, in his first full season racing internationally, had a personal-best 17th-place effort. He finished in 1:37.543.
Loch's teammates Tobias Wendl and Tobias Arlt, winners of five of seven World Cup doubles events to date, were not threatened either in winning the gold medal ahead of compatriots Toni Eggert and Sascha Benecken.
Wendl and Arlt had a two-heat aggregate time of 1:12.842. Eggert and Benecken won silver in 1:13.042.
Only Austrian brothers Andreas and Wolfgang Linger interrupted Germany's dominance. The Lingers, two-time Olympic gold medallists and three-time world champions, captured the doubles bronze with a time of 1:13.268.
Matt Mortensen, of Huntington Station, N.Y., and Preston Griffall, of Salt Lake City settled for 14th place, 0.9 of a second behind Wendl and Arlt.
Jake Hyrns, of Muskegon, Mich., and Andrew Sherk, of Fort Washington, Pa., missed the top 18 cut. They officially placed 21st based on their first heat time.
The two-day world championship event concludes Saturday evening with women's singles followed by the team relay. The latter competition has been added to the Sochi Olympic schedule for next year.