St-Gelais, 24, a three-time Olympic medalist was the only Canadian to reach the podium on the first day of finals at the Maurice Richard Arena in Montreal. Competition continues tomorrow (at 4 p.m. local time on CBC, streamed live at CBCSports.ca at 3 p.m. ET) with 500, 1000 and relay events on the schedule.
St-Gelais, who won three medals at the season-opening event in Salt Lake City, including gold in the 1000, finished second to China's Fan Kexin in the ladies' 500 metre race.
China also took the men's 500, with Wu Dajing topping Dimitry Migunov of Russia, followed by Kwak Yoon-Gy of Korea. Bronze went to Shim Suk Hee of Korea.
Korea swept the 1500 metre finals with Choi Minjeong edging Arianne Fontana of Italy in the ladies event, while Park Se Yeong defeated his countryman Sin Da Woon in the men's race. Sjinkie Knegt of the Netherlands took the bronze.
Canada's multiple Olympic medalist Charles Hamelin was eliminated in the 1500 heats when he collided with another skater and did not finish.
Hamelin, who won a silver in Salt Lake City in the first event of the season, returns on Sunday as does St-Gelais, in individual events as well as the relay A finals for Canada's ladies.